Understanding the Pentose Phosphate Pathway

Hi Ningenerds, in this video we're going to talk about the pentose phosphate pathway. Now the pentose phosphate pathway is a very very important pathway and what's gonna happen is we're gonna see exactly how important it is throughout the series of this video but it's going to be extremely extremely important for synthesis reactions. For example, synthesizing neurotransmitters, synthesizing lipids, cholesterol, synthesizing nucleotides, you know synthesizing many many different types of things. So we're going to see that this is a very very important step also it's very very important for free radical reactions. So we'll see. see exactly how all this is happening. Now, if you guys remember, let's say I bring glucose into the cell, right? So I bring glucose. I'm going to represent with a G. I'm bringing this into the cell, but you know that it can't just pass through the cell membrane. You know, it has to have a special type of glut transporter, right? So let's just say that this is a liver cell. If it's a liver cell, you know that the liver cell has glut 2 transporters. So let's say that this is a liver cell. cell and this is having glut 2 transporters, but whatever. We bring this glucose into the cell. Once we bring this glucose into the cell, so now let's say here's our glucose. If you guys remember, glucose can be acted on by a special enzyme present inside of the liver and it's a special one. That enzyme is called glucokinase. So the enzyme here is called glucosidase. called glucokinase. Now glucokinase is doing what? It's putting a phosphate on the sixth carbon of glucose. So let's now do that. Let's actually represent that. So now what's going to happen? We're going to have glucose here, but we're going to have a phosphate that's If you guys remember, in this step, what are we going to do? We're going to take ATP and convert it into ADP because this glucokinase is going to take and transfer one of the phosphates off of the ATP onto the glucose. So now on the 6-carbon of glucose, I have a phosphate group. So this is my glucose 6-phosphate. So now what am I going to do with this glucose 6-phosphate? Well, there's two things I can do with it. One thing is I can run this puppy through glycolysis. right? I could run this sucker right through glycolysis. So let's run it through glycolysis really, really quickly. Ready? So what are some of the steps of glycolysis? If you guys remember, I can take glucose 6-phosphate, convert it into fructose 6-phosphate. Then, if you guys remember, from that fructose 6-phosphate, I can then do what? I can convert that into fructose 1,6-bisphosphate. So in this step, I can convert fructose 6-phosphate into fructose 1,6-bisphosphate. But remember, this step required ATP. So ATP is being utilized in this step. And we're converting this molecule now into fructose. 1,6-bisphosphate. Okay? 1,6-bisphosphate. Then what happened, if you guys remember? The fructose 1,6-bisphosphate split by an aldolase enzyme, right? And got converted into... dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. And then you know that these guys can isomerize between each other, right? Then the glyceraldehyde 3-phosphate did what? It went through a series of reactions. Like what? It went to 1,3- BPG to what then it actually went to three phosphoglycerate to two phosphoglycerate to phosphoenolpyruvate to pyruvate and it just keeps going and going and going right But, throughout a series of these steps, you guys remember that you generate what? You generate an ATP, you take an ADP here, and you make ATP, but this happens twice. Because when you split fructose 1,6-bisphosphate, you get one of this guy and one of this guy. but most of it funnels into this guy so technically you have two of him two of him two of him two of him two of him and two of him so technically I generate two ATP in this step Another thing is, right here going from 1,3-bisphosphoglycerate to 3-phosphoglycerate, I also generate another ATP, but again, two of them because this pathway occurs twice. So in general, how many ATP did I produce out of all of this? I produced four ATP, right? But that was the gross ATP. Because I used two ATP in the beginning of the process, I actually only netted really... to ATP. Only really netted two ATP. Okay, now this is going to be important that we understand that this glucose 6-phosphate can go through this pathway. It just depends upon the body's needs. Now we're gonna take this puppy and run it through the pentose phosphate pathway. I want to show you how the glycolysis pathway and how the pentose phosphate pathway are so intertwined and interconnected. So now look. This is an important step. I am going to make this step blue. This step right here is extremely important. Okay, so in this step here I'm going to take glucose 6 phosphate and I'm going to convert into a really really funky name. I hate that they call it this but it's how it is. It's called 6-phosphoglucano- Now that's a mouthful, right? But again, what is this molecule here called? It's called 6-phosphoglucanolactone. What happens in this step is going from glucose 6-phosphate to 6-phosphoglucanolactone, I'm going to reduce the glucose 6-phosphate. So in order for me to reduce him, what kind of molecule would I need in order for this to... I'm sorry, actually I'm not reducing glucose 6-phosphate, I'm oxidizing glucose 6-phosphate. So I need a special molecule. A special molecule in this step is going to be NADP positive. I'm going to take this NADP positive across this step, and you know what he's going to do? He's going to pick up some hydride ions. You guys remember hydrides? Hydrides are just basically me saying I have a hydrogen with a proton and two electrons, right? With an overall kind of a negative charge there. That's a hydride. That's what a hydride is. It's a proton with two electrons. He's going to pick up some hydrides from the glucose 6-phosphate and get converted into 6-phosphogluconolactone. Now, in order for that to happen, if you guys remember, anytime you see NAD or NADPH, always remember that there is a dehydrogenase enzyme there. So this enzyme here is going to be extremely important. He is called glucose 6. Phosphate dehydrogenase. So again this enzyme is called glucose 6-phosphate dehydrogenase. Extremely important enzyme because this is going to be one of the enzymes that determines whether this glucose 6-phosphate goes into 6-phosphogluconolactone. And we'll talk about that when we discuss regulation. Now the 6-phosphogluconolactone can then go into another step. Look what's going to happen here. I'm going to take the 6-phosphogluconolactone and I'm going to convert it into another molecule. But specifically, all I'm going to really do in this step is I'm just going to add some water. So I'm going to add some water in this step and I might get out a proton as a result, but either way I'm just adding some water into the step. It's not really that important of a step, but I just want to mention it. And again, this is actually going to be called 6-phosphogluconate. So what happens is I take 6-phosphogluconolactone, add a little bit of water into this step, and get 6-phosphogluconate. Now 6-phosphogluconate, whenever I form him, I'm going to go into this really, really important step here in just a second. Now if you want to know this enzyme, you can. It's called lactanase. So it's called lactonase. Don't get that confused with lactase. That's an enzyme that actually converts, you know... lactose into glucose and galactose. But now what I'm gonna do is I'm gonna take this lactinase enzyme I'm gonna convert 6-phosphogluconolactone into 6-phosphogluconate. Now I'm gonna go on to another important step. In this next step, let's actually do this step in pink. This is another important step here. I am going to generate another set of NADPHs here. So I'm gonna take another NADP positive and convert it into NADPH. Now, to clarify something, glucose 6-phosphate is 6 carbons. Let's put that right up here above it. 6 carbons. This is a 6-carbon molecule. 6-phosphogluconolactone is a 6-carbon molecule. 6-phosphogluconolactone is a 6-carbon molecule. This next molecule that we're going to talk about is called When 6-phosphoglyconolactone is acted on by NADP positive to NADPH, I'm going to form a molecule called ribulose 5-phosphate. Now, when I form ribulose 5-phosphate, this is important in the reason why... Why this one is important is because he's going to get ready to turn into another molecule that we use for a lot of different processes, like synthesizing nucleotides, synthesizing DNA, synthesizing RNA, synthesizing NADs and FADs and coenzyme A. We'll talk about that. We'll list it. But this carbon, ribulose 5-phosphate, is a 5-carbon molecule. So what does that mean if I went from a 6-carbon molecule to a 5-carbon molecule? That means I lost a carbon in the form of CO2. So there was some type of decarboxylation reaction. Decarboxylation. You know, decarboxylation is just basically when you're removing a carbon in the form of CO2. Just like carboxylation would be adding in a carbon in the form of CO2 or sometimes even bicarbonate. Okay, now we got this ribulose 5-phosphate. There's two fates of this ribulose 5-phosphate. Oh, what is the enzyme that catalyzes this step? This step right here is catalyzed by 6-phosphogluconate dehydrogenase. Now this enzyme isn't as important as glucose 6-phosphate dehydrogenase. This enzyme is important nonetheless, but it is not as important or not as significant as compared to glucose 6-phosphate dehydrogenase. There's a condition that we'll talk about. With respect to this glucose 6-phosphate dehydrogenase, if he's deficient it can lead to a certain type of hemolytic anemia with Heinz body formation. Alright, this ribulose 5-phosphate, what can happen with this ribulose 5-phosphate? I can take this ribulose 5-phosphate and I'm going to have two fates for it. One fate is going to be for the formation of two different molecules, but it depends upon the enzyme. Now, ribulose 5-phosphate, if it's acted on by a special enzyme, and this enzyme is an isomerase enzyme. So let's say that there's an isomerase. You know, all isomerases are doing is they're just shuffling different carbons around. So, for example, I can shift ribulose to another molecule, and this new molecule that I'm going to form is called ribose 5. phosphate. Okay, so now I'm gonna have my ribose 5-phosphate and then I'm gonna have my ribulose 5-phosphate. All I'm doing is I'm switching around different types of atoms. For example, this ribulose 5-phosphate can actually be converted into another molecule. You know this molecule is called ribose. 5-phosphate. Now the only difference between ribose 5-phosphate and ribulose 5-phosphate is all I'm doing is I'm switching. You know ribulose 5-phosphate is in the ketone form? You know ketone is basically when you have a carbon here, let's say I have a carbon here and it's got a double bond oxygen and it's in between two carbons. This is a ketone. So this has a ketone form. Whereas ribose is a aldehyde. So you know aldehyde. aldehydes, they're specifically having a carbon double bonded to an oxygen with another carbon, and then on the other part they have a hydrogen. All I'm doing is I'm utilizing this enzyme which is called an isomerase to switch the ketone to an aldehyde. That's all that's happening here. So nothing crazy, I'm just shifting around a little bit with these oxygens, right? Just shifting around a little bit. So I'm shifting a ketone into an aldehyde. Now this other one is extremely interesting. We'll talk about this more in organic chemistry. But this enzyme is called a epimerase. So it's called, for example, this is ribulose 5-phosphate isomerase. This is ribose 5-phosphate epimerase, but specifically on the third carbon. So it's actually occurring on the third carbon. Now, I'm going to really, really dumb this down, because we're going to talk about it. But what we're going to make now is, as a result of taking this epimerase enzyme and converting ribulose 5-phosphate, I'm going to convert this into xylulose. 5-phosphate. Now what is the difference between ribulose 5-phosphate, or I'm sorry, between ribose 5-phosphate and xylulose 5-phosphate really? Because when I'm taking this guy and converting it into ribose 5-phosphate I'm just having isomerization. reaction. When I'm taking ribulose 5-phosphate and converting into xylulose 5-phosphate, I'm utilizing this epimerase enzyme. Now, epimers are basically what's called diastereomers. Like I said, we'll talk about this more in organic, but this is called a diastereomer. What it means is that they differ in chirality, in one carbon. So for example, let's say for example on the third carbon, so let's say that on the third carbon, the fourth carbon, and the fifth carbon of this molecule versus the third carbon, fourth carbon, and fifth carbon of this molecule. Let's say that the ribulose 5-phosphate was R, meaning that it rotates to the right, I'm sorry clockwise, this one rotates counterclockwise and let's say that this one rotates counterclockwise. If they were complete what's called enantiomers, the stereocenters would invert and they would turn into SRR. But the difference is that these are not enantiomers. They're diastereomers, so they differ in only one stereocenter. So, for example, instead of them being, let's say they're RSS, this would be RRR. The only stereocenter that they're now differing in with respect to each other is now going to be this third carbon. They're going to have the same point there, but they're going to now have these carbons being the inverted form. Okay, so they're diastereomers. They're not completely enantiomers, they're differing in one stereocenter. Okay, anyway, that's enough for the organic part of it. Now what I'm going to do is, I'm going to take these two molecules, and I'm going to fuse them together. That's what I'm going to do here. I'm going to take the xylulose 5-phosphate, and I'm going to take... The ribose 5-phosphate, I'm going to fuse these two together. When I do that, I'm going to have a special enzyme working on these two guys. This enzyme we're going to call a transketolase enzyme. So this is going to be called a transketolase enzyme. You know what's special about transketolase enzymes? They have thiamine pyrophosphate as a component of them. You know thiamine pyrophosphate is one of the vitamins? It's a very, very important vitamin, right? So thiamine... Vitamin B1 is very very important in this step because it's gonna act as a coenzyme, the thiamine pyrophosphate. What's happening is transketolase is going to transfer a 2-carbon, so it's transferring two carbons. I know it might seem funky the way I remember it but it helps me. I like to think that a ketone is in between two carbons so it helps me to just simply being able to remember that this guy's transferring two carbons. So he's going to transfer two carbons. So what happens is I'm going to transfer this ribose 5-phosphate. Let's say I take two carbons from him, and I transfer it onto the xylose 5-phosphate. So I'm going to lose two carbons from him. So he's going to go from, again, this is five carbons. This is five carbons here. Nothing changed. All I did was I had isomerization and epimerization. This five carbon and this five carbon, I'm going to transfer two onto him, and he's going to gain two. That means he'll turn into a three-carbon fragment. That three carbon fragment is called glyceraldehyde. I'm going to put glyceraldehyde 3-phosphate. We're just going to abbreviate it here. So again, this is called glyceraldehyde 3-phosphate. That's one product of this reaction. So one product is going to be glyceraldehyde 3-phosphate. Now this one gains the two carbons. So he transfers two carbons onto the xylulose 5-phosphate. And the xylulose 5-phosphate gets converted into what's called sedulo. Hepatose 7-phosphate. Oh sweet goodness. Okay, so Cedulohepatose 7-phosphate is now formed. And it's easy to think, you know, because it's by coincidence that the number that the phosphate's on tells you how many carbons there is. So for example, ribose 5-phosphate, it just so happens to be 5 carbons. Xylulose 5-phosphate, just so happens to be 5 carbons. Glyceraldehyde 3-phosphate, just so happens to be 3 carbons. Cedulo-hepto-7-phosphate just so happens to be seven carbons. But we know that because this was five, this was five, and all I did was I transferred two carbons from him to him. Okay, now what can happen is this glyceride I3-phosphate has two destinations. One is you guys have probably recognized that these are the two same molecules. So what can happen with this glyceride I3-phosphate depending upon the body's demands, which we'll talk about. He could technically get fed. into the glycolytic pathway. Let's show that here. So technically this guy could get converted right here. He could actually be fed into glycolysis if we need to. Okay. Or he could be involved in gluconeogenesis. It just depends upon the body's demands, which we'll talk about because gluconeogenesis, we can make glucose. Glycolysis, we'll go and make ATP. Okay. But let's say that we don't need that. We need to do something else. Let's say we need to make We need to do another process. So now what I'm going to do is I'm going to take this glyceride 3-phosphate and I'm going to combine it with the Cedulo-Hepto-7-phosphate. So now I'm going to fuse these two guys together. So now this guy here and this guy here. are going to react. Okay. What happens here? There's another enzyme. Let's do this one in a different color. Let's do this one in black. This is going to be called a transaldolase. And this one is going to be transferring three carbons. So again, I just like to remember ketone, it's in between two carbons. So it transfers two carbon fragments. As default, trans-adlylase transfers three carbons. Okay? So what is he going to do? Well, he only has three carbons. So he can't lose them. This guy has seven. He can definitely donate. So what he's going to do is he's going to take three carbons from this guy and transfer them onto glyceride 3-phosphate. So then what happens to the glyceride 3-phosphate? Well, he gains three carbons. When he gains three carbons, he turns them into another familiar molecule that I know you guys have heard of called fructose 6-phosphate. phosphate. Where have we seen fructose 6 phosphate before? I know I've seen it in glycolysis. So where can this go then? It can get fed up into fructose 6 phosphate. So we'll just show you. like this for right now. It can get fed into the glycolytic pathway, but depending upon the body's needs it might go somewhere else. But when the sedulohepto-7-phosphate, when there's the three carbons transferred from him, he loses three carbons. So what happens to him then? He loses three carbons and turns into a four carbon molecule. That four carbon molecule is called erythrose. 4-phosphate. Okay, now you guys can imagine fructose 6-phosphate just by coincidence. The phosphate is on the 6-carbon. How many carbons will he have? then. He will have six carbons. And again, this is just by coincidence that all this is happening, but it's nice. Erythrose 4-phosphate. You can imagine that it would have four carbons. Okay. Now you think we're done, but we're not. Okay. We got one more thing that can happen. This erythrose 4-phosphate, I can do something else with it. I can react it with another molecule that we might have just hanging around there. There's another molecule hanging around. And this one is called, okay, let's say, you remember that ribulose 5-phosphate? That ribulose 5-phosphate? Let's say I have another ribulose 5-phosphate over here. And that ribulose 5-phosphate, I have it acted on by an epimerase enzyme. If it's acted on by an epi... Merase enzyme, what does it get converted into? You guys know that it gets converted into, specifically, xylulose 5-phosphate. Okay, well now, what the body is going to do is, it's going to take this xylulose 5-phosphate, and it's going to react it with this erythrose 4-phosphate. Now, if these two react... The xylulose 5-phosphate and the erythrophosphate are going to be acted on by another enzyme. That enzyme is called a transketolase enzyme. So I'm going to have another enzyme which is called a transketolase enzyme. And again, it has thiamine pyrophosphate as a coenzyme here. And again, it's transferring how many carbons? It's transferring two carbons. So it's a two-carbon transferring enzyme. It's going to transfer two carbons from the xylose 5-phosphate onto the erythrophosphate. Now, if he's transferring two carbons, then this five carbon will lose two carbons and turn into a three carbon molecule. This three carbon molecule is called glyceraldehyde 3-phosphate. Not so bad. And we already know where he can go. We'll just draw a red line for right now, showing it feeding over here into glycolysis. But the two carbons that are transferred from this five carbon molecule are put onto this four carbon molecule. and it leads to the formation of fructose 6-phosphate. And now we've synthesized this fructose 6-phosphate and you guys already know where can this fructose 6-phosphate go. He can also be fed into glycolysis. Okay this step here one, two, Three and four. These four steps here are involved in a specific part of the pentose phosphate pathway because it's actually divided into Two parts. What are the two parts here? One is actually called the oxidative phase. That's the four-step one, okay? This is the four-stepper, the four-step one that we went over. And what is that including? Again, it includes glucose 6-phosphate going to glucose 6-phosphate dehydrogenate. I'm sorry, glucose 6-phosphate being acted on by glucose 6-phosphate dehydrogenase to make 6-phosphogluconolactone. 6-phosphogluconolactone being acted on by lactanase to make 6-phosphogluconate. 6-phosphogluconate being acted on by 6-phosphogluconate dehydrogenase, which is also going to convert NADP positive to NADPH, and generating a CO2 to make ribulose 5-phosphate, and then the conversion of ribulose 5-phosphate into ribose 5-phosphate and xylose 5-phosphate. That is the oxidative phase. The main purpose of the oxidative phase is two things. One thing is to make NADPH and the other thing is to make ribose 5-phosphate. That is the purpose of the oxidative phase. It's to make a lot of NADPH and to make a lot of ribose 5-phosphate. Now, we'll talk about why that's important in just a second, but what's the other phase? The other phase is actually called the non-oxidative. phase. And I like to think about this one as just that carbon shuffling reactions. Carbon shuffling reactions. In other words, you see all these steps here afterwards, after the fourth step. So in other words, this step here, we can technically say the fifth step, the sixth step, the seventh step, all those, all these carbon shuffling where I'm going from Ribose 5-phosphate and xylose 5-phosphate into glyceride 3-phosphate and sedulo heptose 7-phosphate. These two reacting and forming fructose 6-phosphate and erythrose 4-phosphate. This guy reacting with the xylose 5-phosphate to make glyceride 3-phosphate and fructose 6-phosphate. Those are my carbon shuffling reactions. And what these are good for is that I didn't really show it here, but look at this. You see this step here, me going from ribose 5-phosphate to glyceride 3-phosphate? This is reversible. This going from here. Reversible, reversible, reversible, and this is also reversible and reversible. What does that mean? That means I can take things from glycolysis, like what? Like the glyceride 3-phosphate and help to make ribose 5-phosphate. So I can actually take glyceride 3-phosphate, fructose 6-phosphate and do what? React these two together to get erythrosophore phosphate and xylulose 5-phosphate, which can actually be converted into ribose 5-phosphate. Eventually, right? Then what happens? Then I can take that erythrox 4-phosphate, react it with another glycolytic intermediate and make glyceride I3-phosphate and seduloheptose. If these two react, I can get ribose 5-phosphate and xylose 5-phosphate. So from the non-oxidative pathway, what can I do? I can make ribose, I'm going to put R5P, I'll just do it, ribose 5-phosphate without. Making NADPH. And this can come from glycolytic intermediates. So the whole significance of this pentose phosphate pathway is that I have two phases. The oxidative phase, which is generating a lot of NADPHs and a lot of ribose 5-phosphate. And the non-oxidative phase, which is all those carbon shuffling reactions, which the whole purpose is is I can make ribose 5-phosphate without making NADPH, and I can use glycolytic intermediates, or I can take ribose 5-phosphate and make glycolytic intermediates. So in the reverse concept, I could take ribose 5-phosphate, I'm going to put R5P, and convert that into glycolytic intermediates. So that is pretty cool. Okay, so now that we understand this process here, let me just mention here, What is the significance of NADPH? What is the significance of ribose 5-phosphate? And then we're going to stop this video and do another video on the regulation. Okay, let's take here and say NADPH. I already told you guys that NADPH is very, very good at being a good reducing agent. He has reducing power, they call it, right? So he's a good reducing agent. He has reducing power. For what type of reactions? For any type of... Biosynthetic reaction. What do I mean? Well if you guys have watched a lot of these metabolism videos you know that he's good for fatty acid synthesis. We need him in a lot of those fatty acid synthesis steps, specifically the reduction steps. If you guys watch the cholesterol metabolism video, he's also important in cholesterol metabolism for being able to convert the HMG-CoA into the Mevalonate. And he's also good for other different types of processes. Like one of them is specifically called nucleotides. You actually need it for the nucleotide metabolism, so synthesis of nucleotides. And we didn't talk about it too much, but it's also needed for neurotransmitter synthesis. A lot of different things that this sucker can be used for. And we'll talk about a lot of these things like the nucleotide synthesis and the neurotransmitter synthesis in individual systems and videos. But just realize that this guy has a lot of significant things that he's involved in. He's significant for making fatty acids, cholesterol, nucleotides, and neurotransmitters. What about ribose 5-phosphate? Ribose 5-phosphate is equally as important. You'll see I should actually put one more thing in here if I can squeeze it in there. Let me actually just erase this I'm really really important thing that I did not mention. It's also good for free radical reactions, and we'll discuss that in the next video Really, really important for free radical reactions. It's acting as what's called an antioxidant, basically. And you'll see exactly how it's helping. It's not technically an antioxidant, but it's helping antioxidant enzymes. Okay, and the last one we said was ribose. 5-phosphate. Now ribose 5-phosphate is important because he is involved in making a lot of different nucleotides. Like what? You know he's important for making, you know, nucleotides that are specific for nucleic acids because you know nucleotides are the basic building blocks for the nucleic acids like what like DNA RNA oh it's also good for making ATP they actually use it as a building block for ATP we use it for those electron shuttles within the Krebs cycle you guys have heard of them NAD positive and FAD. He's good for making these and he's also good for making coenzyme A. So he is very important in the synthesis of a lot of these different. I'm going to put here synthesis and then same thing. So ATP synthesis, NAD positive synthesis, FAD synthesis, coenzyme A synthesis. So he's very, very important. So you can imagine why these things are so significant. Any type of alteration. within these could lead to disastrous effects. Specifically one that we'll talk about with respect to the free radical reactions is if there's a deficiency in a specific enzyme that generates these they can develop what's called a hemolytic anemia with Heinz bodies. So put Heinz bodies for now. Okay we'll talk about that in the next video. Okay so now we understand the the way that this pathway is occurring that the two phases oxidative phase which real quickly glucose 6-phosphate to 6-phosphogluconolactone, 6-phosphogluconolactone to 6-phosphogluconate, 6-phosphogluconate into ribulose 5-phosphate, and just the isomerization or epimerization to ribose 5-phosphate and xylulose 5-phosphate. These are the oxidative phases, okay? But the non-oxidative phases is all these carbon shuffling reactions. So when I take ribose 5-phosphate and xylulose, react them with the transketolase, react glyceride 3-phosphate, seduloheptase with a... trans-autolase and then reacting xylulose 5-phosphate with erythrophosphate with the trans-ketolase and making different glycolytic intermediates. This is important for making ribose 5-phosphate without needing to make NADPH or as well as taking ribose 5-phosphate and making specific glycolytic intermediates, which also can be used in gluconeogenesis. And we'll talk about that in the next video. All right, guys, I hope all this made sense. I hope you guys did enjoy it. If you did, hit that like button, subscribe, please, and please comment down in the comment section. We look forward to hearing from you guys. All right, in the next video, we'll go on to this in a little bit more detail. All right, Ninja Nerds, until next time.

So we'll see. see exactly how all this is happening. Now, if you guys remember, let's say I bring glucose into the cell, right?

So I bring glucose. I'm going to represent with a G. I'm bringing this into the cell, but you know that it can't just pass through the cell membrane. You know, it has to have a special type of glut transporter, right?

So let's just say that this is a liver cell. If it's a liver cell, you know that the liver cell has glut 2 transporters. So let's say that this is a liver cell. cell and this is having glut 2 transporters, but whatever. We bring this glucose into the cell.

Once we bring this glucose into the cell, so now let's say here's our glucose. If you guys remember, glucose can be acted on by a special enzyme present inside of the liver and it's a special one. That enzyme is called glucokinase.

So the enzyme here is called glucosidase. called glucokinase. Now glucokinase is doing what?

It's putting a phosphate on the sixth carbon of glucose. So let's now do that. Let's actually represent that. So now what's going to happen?

We're going to have glucose here, but we're going to have a phosphate that's If you guys remember, in this step, what are we going to do? We're going to take ATP and convert it into ADP because this glucokinase is going to take and transfer one of the phosphates off of the ATP onto the glucose. So now on the 6-carbon of glucose, I have a phosphate group.

So this is my glucose 6-phosphate. So now what am I going to do with this glucose 6-phosphate? Well, there's two things I can do with it.

One thing is I can run this puppy through glycolysis. right? I could run this sucker right through glycolysis.

So let's run it through glycolysis really, really quickly. Ready? So what are some of the steps of glycolysis? If you guys remember, I can take glucose 6-phosphate, convert it into fructose 6-phosphate.

Then, if you guys remember, from that fructose 6-phosphate, I can then do what? I can convert that into fructose 1,6-bisphosphate. So in this step, I can convert fructose 6-phosphate into fructose 1,6-bisphosphate. But remember, this step required ATP. So ATP is being utilized in this step.

And we're converting this molecule now into fructose. 1,6-bisphosphate. Okay? 1,6-bisphosphate.

Then what happened, if you guys remember? The fructose 1,6-bisphosphate split by an aldolase enzyme, right? And got converted into...

dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. And then you know that these guys can isomerize between each other, right? Then the glyceraldehyde 3-phosphate did what?

It went through a series of reactions. Like what? It went to 1,3- BPG to what then it actually went to three phosphoglycerate to two phosphoglycerate to phosphoenolpyruvate to pyruvate and it just keeps going and going and going right But, throughout a series of these steps, you guys remember that you generate what?

You generate an ATP, you take an ADP here, and you make ATP, but this happens twice. Because when you split fructose 1,6-bisphosphate, you get one of this guy and one of this guy. but most of it funnels into this guy so technically you have two of him two of him two of him two of him two of him and two of him so technically I generate two ATP in this step Another thing is, right here going from 1,3-bisphosphoglycerate to 3-phosphoglycerate, I also generate another ATP, but again, two of them because this pathway occurs twice.

So in general, how many ATP did I produce out of all of this? I produced four ATP, right? But that was the gross ATP. Because I used two ATP in the beginning of the process, I actually only netted really...

to ATP. Only really netted two ATP. Okay, now this is going to be important that we understand that this glucose 6-phosphate can go through this pathway. It just depends upon the body's needs.

Now we're gonna take this puppy and run it through the pentose phosphate pathway. I want to show you how the glycolysis pathway and how the pentose phosphate pathway are so intertwined and interconnected. So now look.

This is an important step. I am going to make this step blue. This step right here is extremely important.

Okay, so in this step here I'm going to take glucose 6 phosphate and I'm going to convert into a really really funky name. I hate that they call it this but it's how it is. It's called 6-phosphoglucano- Now that's a mouthful, right? But again, what is this molecule here called?

It's called 6-phosphoglucanolactone. What happens in this step is going from glucose 6-phosphate to 6-phosphoglucanolactone, I'm going to reduce the glucose 6-phosphate. So in order for me to reduce him, what kind of molecule would I need in order for this to...

I'm sorry, actually I'm not reducing glucose 6-phosphate, I'm oxidizing glucose 6-phosphate. So I need a special molecule. A special molecule in this step is going to be NADP positive. I'm going to take this NADP positive across this step, and you know what he's going to do? He's going to pick up some hydride ions.

You guys remember hydrides? Hydrides are just basically me saying I have a hydrogen with a proton and two electrons, right? With an overall kind of a negative charge there. That's a hydride.

That's what a hydride is. It's a proton with two electrons. He's going to pick up some hydrides from the glucose 6-phosphate and get converted into 6-phosphogluconolactone.

Now, in order for that to happen, if you guys remember, anytime you see NAD or NADPH, always remember that there is a dehydrogenase enzyme there. So this enzyme here is going to be extremely important. He is called glucose 6. Phosphate dehydrogenase. So again this enzyme is called glucose 6-phosphate dehydrogenase. Extremely important enzyme because this is going to be one of the enzymes that determines whether this glucose 6-phosphate goes into 6-phosphogluconolactone.

And we'll talk about that when we discuss regulation. Now the 6-phosphogluconolactone can then go into another step. Look what's going to happen here. I'm going to take the 6-phosphogluconolactone and I'm going to convert it into another molecule. But specifically, all I'm going to really do in this step is I'm just going to add some water.

So I'm going to add some water in this step and I might get out a proton as a result, but either way I'm just adding some water into the step. It's not really that important of a step, but I just want to mention it. And again, this is actually going to be called 6-phosphogluconate.

So what happens is I take 6-phosphogluconolactone, add a little bit of water into this step, and get 6-phosphogluconate. Now 6-phosphogluconate, whenever I form him, I'm going to go into this really, really important step here in just a second. Now if you want to know this enzyme, you can. It's called lactanase. So it's called lactonase.

Don't get that confused with lactase. That's an enzyme that actually converts, you know... lactose into glucose and galactose.

But now what I'm gonna do is I'm gonna take this lactinase enzyme I'm gonna convert 6-phosphogluconolactone into 6-phosphogluconate. Now I'm gonna go on to another important step. In this next step, let's actually do this step in pink. This is another important step here. I am going to generate another set of NADPHs here.

So I'm gonna take another NADP positive and convert it into NADPH. Now, to clarify something, glucose 6-phosphate is 6 carbons. Let's put that right up here above it.

6 carbons. This is a 6-carbon molecule. 6-phosphogluconolactone is a 6-carbon molecule. 6-phosphogluconolactone is a 6-carbon molecule.

This next molecule that we're going to talk about is called When 6-phosphoglyconolactone is acted on by NADP positive to NADPH, I'm going to form a molecule called ribulose 5-phosphate. Now, when I form ribulose 5-phosphate, this is important in the reason why... Why this one is important is because he's going to get ready to turn into another molecule that we use for a lot of different processes, like synthesizing nucleotides, synthesizing DNA, synthesizing RNA, synthesizing NADs and FADs and coenzyme A. We'll talk about that. We'll list it.

But this carbon, ribulose 5-phosphate, is a 5-carbon molecule. So what does that mean if I went from a 6-carbon molecule to a 5-carbon molecule? That means I lost a carbon in the form of CO2.

So there was some type of decarboxylation reaction. Decarboxylation. You know, decarboxylation is just basically when you're removing a carbon in the form of CO2. Just like carboxylation would be adding in a carbon in the form of CO2 or sometimes even bicarbonate. Okay, now we got this ribulose 5-phosphate.

There's two fates of this ribulose 5-phosphate. Oh, what is the enzyme that catalyzes this step? This step right here is catalyzed by 6-phosphogluconate dehydrogenase.

Now this enzyme isn't as important as glucose 6-phosphate dehydrogenase. This enzyme is important nonetheless, but it is not as important or not as significant as compared to glucose 6-phosphate dehydrogenase. There's a condition that we'll talk about.

With respect to this glucose 6-phosphate dehydrogenase, if he's deficient it can lead to a certain type of hemolytic anemia with Heinz body formation. Alright, this ribulose 5-phosphate, what can happen with this ribulose 5-phosphate? I can take this ribulose 5-phosphate and I'm going to have two fates for it. One fate is going to be for the formation of two different molecules, but it depends upon the enzyme.

Now, ribulose 5-phosphate, if it's acted on by a special enzyme, and this enzyme is an isomerase enzyme. So let's say that there's an isomerase. You know, all isomerases are doing is they're just shuffling different carbons around.

So, for example, I can shift ribulose to another molecule, and this new molecule that I'm going to form is called ribose 5. phosphate. Okay, so now I'm gonna have my ribose 5-phosphate and then I'm gonna have my ribulose 5-phosphate. All I'm doing is I'm switching around different types of atoms.

For example, this ribulose 5-phosphate can actually be converted into another molecule. You know this molecule is called ribose. 5-phosphate. Now the only difference between ribose 5-phosphate and ribulose 5-phosphate is all I'm doing is I'm switching.

You know ribulose 5-phosphate is in the ketone form? You know ketone is basically when you have a carbon here, let's say I have a carbon here and it's got a double bond oxygen and it's in between two carbons. This is a ketone. So this has a ketone form. Whereas ribose is a aldehyde.

So you know aldehyde. aldehydes, they're specifically having a carbon double bonded to an oxygen with another carbon, and then on the other part they have a hydrogen. All I'm doing is I'm utilizing this enzyme which is called an isomerase to switch the ketone to an aldehyde. That's all that's happening here. So nothing crazy, I'm just shifting around a little bit with these oxygens, right?

Just shifting around a little bit. So I'm shifting a ketone into an aldehyde. Now this other one is extremely interesting. We'll talk about this more in organic chemistry. But this enzyme is called a epimerase.

So it's called, for example, this is ribulose 5-phosphate isomerase. This is ribose 5-phosphate epimerase, but specifically on the third carbon. So it's actually occurring on the third carbon. Now, I'm going to really, really dumb this down, because we're going to talk about it.

But what we're going to make now is, as a result of taking this epimerase enzyme and converting ribulose 5-phosphate, I'm going to convert this into xylulose. 5-phosphate. Now what is the difference between ribulose 5-phosphate, or I'm sorry, between ribose 5-phosphate and xylulose 5-phosphate really? Because when I'm taking this guy and converting it into ribose 5-phosphate I'm just having isomerization.

reaction. When I'm taking ribulose 5-phosphate and converting into xylulose 5-phosphate, I'm utilizing this epimerase enzyme. Now, epimers are basically what's called diastereomers. Like I said, we'll talk about this more in organic, but this is called a diastereomer. What it means is that they differ in chirality, in one carbon.

So for example, let's say for example on the third carbon, so let's say that on the third carbon, the fourth carbon, and the fifth carbon of this molecule versus the third carbon, fourth carbon, and fifth carbon of this molecule. Let's say that the ribulose 5-phosphate was R, meaning that it rotates to the right, I'm sorry clockwise, this one rotates counterclockwise and let's say that this one rotates counterclockwise. If they were complete what's called enantiomers, the stereocenters would invert and they would turn into SRR.

But the difference is that these are not enantiomers. They're diastereomers, so they differ in only one stereocenter. So, for example, instead of them being, let's say they're RSS, this would be RRR. The only stereocenter that they're now differing in with respect to each other is now going to be this third carbon. They're going to have the same point there, but they're going to now have these carbons being the inverted form.

Okay, so they're diastereomers. They're not completely enantiomers, they're differing in one stereocenter. Okay, anyway, that's enough for the organic part of it.

Now what I'm going to do is, I'm going to take these two molecules, and I'm going to fuse them together. That's what I'm going to do here. I'm going to take the xylulose 5-phosphate, and I'm going to take...

The ribose 5-phosphate, I'm going to fuse these two together. When I do that, I'm going to have a special enzyme working on these two guys. This enzyme we're going to call a transketolase enzyme. So this is going to be called a transketolase enzyme. You know what's special about transketolase enzymes?

They have thiamine pyrophosphate as a component of them. You know thiamine pyrophosphate is one of the vitamins? It's a very, very important vitamin, right?

So thiamine... Vitamin B1 is very very important in this step because it's gonna act as a coenzyme, the thiamine pyrophosphate. What's happening is transketolase is going to transfer a 2-carbon, so it's transferring two carbons. I know it might seem funky the way I remember it but it helps me.

I like to think that a ketone is in between two carbons so it helps me to just simply being able to remember that this guy's transferring two carbons. So he's going to transfer two carbons. So what happens is I'm going to transfer this ribose 5-phosphate.

Let's say I take two carbons from him, and I transfer it onto the xylose 5-phosphate. So I'm going to lose two carbons from him. So he's going to go from, again, this is five carbons. This is five carbons here. Nothing changed.

All I did was I had isomerization and epimerization. This five carbon and this five carbon, I'm going to transfer two onto him, and he's going to gain two. That means he'll turn into a three-carbon fragment. That three carbon fragment is called glyceraldehyde. I'm going to put glyceraldehyde 3-phosphate.

We're just going to abbreviate it here. So again, this is called glyceraldehyde 3-phosphate. That's one product of this reaction. So one product is going to be glyceraldehyde 3-phosphate.

Now this one gains the two carbons. So he transfers two carbons onto the xylulose 5-phosphate. And the xylulose 5-phosphate gets converted into what's called sedulo. Hepatose 7-phosphate. Oh sweet goodness.

Okay, so Cedulohepatose 7-phosphate is now formed. And it's easy to think, you know, because it's by coincidence that the number that the phosphate's on tells you how many carbons there is. So for example, ribose 5-phosphate, it just so happens to be 5 carbons.

Xylulose 5-phosphate, just so happens to be 5 carbons. Glyceraldehyde 3-phosphate, just so happens to be 3 carbons. Cedulo-hepto-7-phosphate just so happens to be seven carbons. But we know that because this was five, this was five, and all I did was I transferred two carbons from him to him. Okay, now what can happen is this glyceride I3-phosphate has two destinations.

One is you guys have probably recognized that these are the two same molecules. So what can happen with this glyceride I3-phosphate depending upon the body's demands, which we'll talk about. He could technically get fed. into the glycolytic pathway.

Let's show that here. So technically this guy could get converted right here. He could actually be fed into glycolysis if we need to.

Okay. Or he could be involved in gluconeogenesis. It just depends upon the body's demands, which we'll talk about because gluconeogenesis, we can make glucose.

Glycolysis, we'll go and make ATP. Okay. But let's say that we don't need that.

We need to do something else. Let's say we need to make We need to do another process. So now what I'm going to do is I'm going to take this glyceride 3-phosphate and I'm going to combine it with the Cedulo-Hepto-7-phosphate.

So now I'm going to fuse these two guys together. So now this guy here and this guy here. are going to react.

Okay. What happens here? There's another enzyme.

Let's do this one in a different color. Let's do this one in black. This is going to be called a transaldolase.

And this one is going to be transferring three carbons. So again, I just like to remember ketone, it's in between two carbons. So it transfers two carbon fragments. As default, trans-adlylase transfers three carbons.

Okay? So what is he going to do? Well, he only has three carbons. So he can't lose them. This guy has seven.

He can definitely donate. So what he's going to do is he's going to take three carbons from this guy and transfer them onto glyceride 3-phosphate. So then what happens to the glyceride 3-phosphate?

Well, he gains three carbons. When he gains three carbons, he turns them into another familiar molecule that I know you guys have heard of called fructose 6-phosphate. phosphate. Where have we seen fructose 6 phosphate before? I know I've seen it in glycolysis.

So where can this go then? It can get fed up into fructose 6 phosphate. So we'll just show you. like this for right now.

It can get fed into the glycolytic pathway, but depending upon the body's needs it might go somewhere else. But when the sedulohepto-7-phosphate, when there's the three carbons transferred from him, he loses three carbons. So what happens to him then?

He loses three carbons and turns into a four carbon molecule. That four carbon molecule is called erythrose. 4-phosphate.

Okay, now you guys can imagine fructose 6-phosphate just by coincidence. The phosphate is on the 6-carbon. How many carbons will he have?

then. He will have six carbons. And again, this is just by coincidence that all this is happening, but it's nice.

Erythrose 4-phosphate. You can imagine that it would have four carbons. Okay. Now you think we're done, but we're not. Okay.

We got one more thing that can happen. This erythrose 4-phosphate, I can do something else with it. I can react it with another molecule that we might have just hanging around there. There's another molecule hanging around. And this one is called, okay, let's say, you remember that ribulose 5-phosphate?

That ribulose 5-phosphate? Let's say I have another ribulose 5-phosphate over here. And that ribulose 5-phosphate, I have it acted on by an epimerase enzyme. If it's acted on by an epi...

Merase enzyme, what does it get converted into? You guys know that it gets converted into, specifically, xylulose 5-phosphate. Okay, well now, what the body is going to do is, it's going to take this xylulose 5-phosphate, and it's going to react it with this erythrose 4-phosphate.

Now, if these two react... The xylulose 5-phosphate and the erythrophosphate are going to be acted on by another enzyme. That enzyme is called a transketolase enzyme.

So I'm going to have another enzyme which is called a transketolase enzyme. And again, it has thiamine pyrophosphate as a coenzyme here. And again, it's transferring how many carbons?

It's transferring two carbons. So it's a two-carbon transferring enzyme. It's going to transfer two carbons from the xylose 5-phosphate onto the erythrophosphate.

Now, if he's transferring two carbons, then this five carbon will lose two carbons and turn into a three carbon molecule. This three carbon molecule is called glyceraldehyde 3-phosphate. Not so bad.

And we already know where he can go. We'll just draw a red line for right now, showing it feeding over here into glycolysis. But the two carbons that are transferred from this five carbon molecule are put onto this four carbon molecule. and it leads to the formation of fructose 6-phosphate.

And now we've synthesized this fructose 6-phosphate and you guys already know where can this fructose 6-phosphate go. He can also be fed into glycolysis. Okay this step here one, two, Three and four. These four steps here are involved in a specific part of the pentose phosphate pathway because it's actually divided into Two parts.

What are the two parts here? One is actually called the oxidative phase. That's the four-step one, okay?

This is the four-stepper, the four-step one that we went over. And what is that including? Again, it includes glucose 6-phosphate going to glucose 6-phosphate dehydrogenate. I'm sorry, glucose 6-phosphate being acted on by glucose 6-phosphate dehydrogenase to make 6-phosphogluconolactone. 6-phosphogluconolactone being acted on by lactanase to make 6-phosphogluconate.

6-phosphogluconate being acted on by 6-phosphogluconate dehydrogenase, which is also going to convert NADP positive to NADPH, and generating a CO2 to make ribulose 5-phosphate, and then the conversion of ribulose 5-phosphate into ribose 5-phosphate and xylose 5-phosphate. That is the oxidative phase. The main purpose of the oxidative phase is two things.

One thing is to make NADPH and the other thing is to make ribose 5-phosphate. That is the purpose of the oxidative phase. It's to make a lot of NADPH and to make a lot of ribose 5-phosphate.

Now, we'll talk about why that's important in just a second, but what's the other phase? The other phase is actually called the non-oxidative. phase.

And I like to think about this one as just that carbon shuffling reactions. Carbon shuffling reactions. In other words, you see all these steps here afterwards, after the fourth step.

So in other words, this step here, we can technically say the fifth step, the sixth step, the seventh step, all those, all these carbon shuffling where I'm going from Ribose 5-phosphate and xylose 5-phosphate into glyceride 3-phosphate and sedulo heptose 7-phosphate. These two reacting and forming fructose 6-phosphate and erythrose 4-phosphate. This guy reacting with the xylose 5-phosphate to make glyceride 3-phosphate and fructose 6-phosphate.

Those are my carbon shuffling reactions. And what these are good for is that I didn't really show it here, but look at this. You see this step here, me going from ribose 5-phosphate to glyceride 3-phosphate? This is reversible.

This going from here. Reversible, reversible, reversible, and this is also reversible and reversible. What does that mean? That means I can take things from glycolysis, like what?

Like the glyceride 3-phosphate and help to make ribose 5-phosphate. So I can actually take glyceride 3-phosphate, fructose 6-phosphate and do what? React these two together to get erythrosophore phosphate and xylulose 5-phosphate, which can actually be converted into ribose 5-phosphate. Eventually, right?

Then what happens? Then I can take that erythrox 4-phosphate, react it with another glycolytic intermediate and make glyceride I3-phosphate and seduloheptose. If these two react, I can get ribose 5-phosphate and xylose 5-phosphate. So from the non-oxidative pathway, what can I do?

I can make ribose, I'm going to put R5P, I'll just do it, ribose 5-phosphate without. Making NADPH. And this can come from glycolytic intermediates.

So the whole significance of this pentose phosphate pathway is that I have two phases. The oxidative phase, which is generating a lot of NADPHs and a lot of ribose 5-phosphate. And the non-oxidative phase, which is all those carbon shuffling reactions, which the whole purpose is is I can make ribose 5-phosphate without making NADPH, and I can use glycolytic intermediates, or I can take ribose 5-phosphate and make glycolytic intermediates. So in the reverse concept, I could take ribose 5-phosphate, I'm going to put R5P, and convert that into glycolytic intermediates. So that is pretty cool.

Okay, so now that we understand this process here, let me just mention here, What is the significance of NADPH? What is the significance of ribose 5-phosphate? And then we're going to stop this video and do another video on the regulation.

Okay, let's take here and say NADPH. I already told you guys that NADPH is very, very good at being a good reducing agent. He has reducing power, they call it, right?

So he's a good reducing agent. He has reducing power. For what type of reactions?

For any type of... Biosynthetic reaction. What do I mean?

Well if you guys have watched a lot of these metabolism videos you know that he's good for fatty acid synthesis. We need him in a lot of those fatty acid synthesis steps, specifically the reduction steps. If you guys watch the cholesterol metabolism video, he's also important in cholesterol metabolism for being able to convert the HMG-CoA into the Mevalonate. And he's also good for other different types of processes. Like one of them is specifically called nucleotides.

You actually need it for the nucleotide metabolism, so synthesis of nucleotides. And we didn't talk about it too much, but it's also needed for neurotransmitter synthesis. A lot of different things that this sucker can be used for.

And we'll talk about a lot of these things like the nucleotide synthesis and the neurotransmitter synthesis in individual systems and videos. But just realize that this guy has a lot of significant things that he's involved in. He's significant for making fatty acids, cholesterol, nucleotides, and neurotransmitters. What about ribose 5-phosphate? Ribose 5-phosphate is equally as important.

You'll see I should actually put one more thing in here if I can squeeze it in there. Let me actually just erase this I'm really really important thing that I did not mention. It's also good for free radical reactions, and we'll discuss that in the next video Really, really important for free radical reactions.

It's acting as what's called an antioxidant, basically. And you'll see exactly how it's helping. It's not technically an antioxidant, but it's helping antioxidant enzymes.

Okay, and the last one we said was ribose. 5-phosphate. Now ribose 5-phosphate is important because he is involved in making a lot of different nucleotides. Like what? You know he's important for making, you know, nucleotides that are specific for nucleic acids because you know nucleotides are the basic building blocks for the nucleic acids like what like DNA RNA oh it's also good for making ATP they actually use it as a building block for ATP we use it for those electron shuttles within the Krebs cycle you guys have heard of them NAD positive and FAD.

He's good for making these and he's also good for making coenzyme A. So he is very important in the synthesis of a lot of these different. I'm going to put here synthesis and then same thing.

So ATP synthesis, NAD positive synthesis, FAD synthesis, coenzyme A synthesis. So he's very, very important. So you can imagine why these things are so significant. Any type of alteration.

within these could lead to disastrous effects. Specifically one that we'll talk about with respect to the free radical reactions is if there's a deficiency in a specific enzyme that generates these they can develop what's called a hemolytic anemia with Heinz bodies. So put Heinz bodies for now. Okay we'll talk about that in the next video.

Okay so now we understand the the way that this pathway is occurring that the two phases oxidative phase which real quickly glucose 6-phosphate to 6-phosphogluconolactone, 6-phosphogluconolactone to 6-phosphogluconate, 6-phosphogluconate into ribulose 5-phosphate, and just the isomerization or epimerization to ribose 5-phosphate and xylulose 5-phosphate. These are the oxidative phases, okay? But the non-oxidative phases is all these carbon shuffling reactions. So when I take ribose 5-phosphate and xylulose, react them with the transketolase, react glyceride 3-phosphate, seduloheptase with a...

trans-autolase and then reacting xylulose 5-phosphate with erythrophosphate with the trans-ketolase and making different glycolytic intermediates. This is important for making ribose 5-phosphate without needing to make NADPH or as well as taking ribose 5-phosphate and making specific glycolytic intermediates, which also can be used in gluconeogenesis. And we'll talk about that in the next video. All right, guys, I hope all this made sense.

I hope you guys did enjoy it. If you did, hit that like button, subscribe, please, and please comment down in the comment section. We look forward to hearing from you guys.

All right, in the next video, we'll go on to this in a little bit more detail. All right, Ninja Nerds, until next time.

Transcript for:Understanding the Pentose Phosphate Pathway

Transcript for:
Understanding the Pentose Phosphate Pathway