now there are 20 amino acids that you need to at least be able to recognize on a test now this isn't going to be like undergraduate school where you have to be able to know each and every one and draw them out chemically it's simply not important for the purposes of medical school but what you should remember is that these are building blocks of protein and they are also metabolic intermediates so that is to say that amino acids themselves can either be cofactors in various biochemical reactions or the amino acids themselves will be used to derive very important end products now there are certain categories that you definitely need to know this is definitely the highest yield part of today's video it's knowing what is an essential amino acid what is a non-essential amino acid which ones are acidic versus which ones are basic which ones are ketogenic glucogenic or a mixture of keto and glucogenic and which ones are branched now if that sounds overwhelming well that's because it is but don't worry because i'm gonna break this down for you we're gonna use charts pictures diagrams and of course some awesome dirty medicine mnemonics to wrap all of this up beautifully beautifully for your studying pleasure so first let's get into the essential versus the non-essential amino acids now taking a step back and keeping the big picture in mind what you should remember is that the essential amino acids cannot be produced by the body and this is why they're essential because it's essential that you get them in your diet since your body can't produce them so that's where the term essential comes from and now obviously non-essential is just going to be the opposite these can be produced by the body so there's no need for them to be obtained in the diet they are non-essential it is not essential that you get them in your diet so the term essential versus non-essential just tells you is it important for this to be in your diet now if you understand that let's show you the different essential amino acids now these are your essential amino acids there's threonine tyrosine valine phenylalanine isoleucine leucine lysine methionine and histidine now moving on the next big category is acidic versus basic and some people think that this is an easy thing to remember but just to really hammer it home i'm going to break it down for you now of course the amino acids with the word acid in their name are the acidic amino acids right it sounds like a no-brainer but you know for completeness sake let's include it here so aspartic acid glutamic acid these are acidic or acidic okay what's probably more important and we'll show up on exams more is what are the basic amino acids and that's where i have a really awesome mnemonic so the basic amino acids are histidine lysine and arginine now how do i remember this if you're familiar with the sh you know what what basic means in today's language for college students uh is not it has an interesting definition and it's not what you might think and i apologize if you're not familiar with americanized urban slang but if you look up basic in the urban dictionary which is an awesome website by the way the urban dictionary's definition of the word basic is of or relating only to mainstream things such as leggings ugg boots pumpkin spice lattes and instagram likes so you know people who went to college undergraduate school in the united states always talk about the basic sorority sister and that's somebody who walks around with leggings ugg boots um looks like every other sorority sister on campus drinks pumpkin spice lattes in the fall and really only does it for the instagram okay so that's what basic means so you may have overheard somebody say wow you're so basic and that doesn't mean wow your ph is such and such it means you are only interested in mainstream things that millennials um and the younger generations are interested in so uh perhaps this mnemonic is not useful to you but it is to me and the way that i remember this is that her leggings are basic hla her leggings are h for histidine l for lysine and a for arginine of course this is a stupid mnemonic but if you're having trouble memorizing that histidine lysine and arginine are basic amino acids then just remember her leggings are basic and you'll have no problem memorizing basic versus acidic so this is the summary kind of easy to remember for the acidic side and for the basic side her leggings are basic now this is a chart that you may have not seen before knowing which amino acids are ketogenic versus glucogenic versus a mixture of ketogenic and glucogenic is something that is very tricky because it's taught very poorly so here's what we have the ketogenic amino acids are leucine and lysine the glucogenic amino acids are histidine methionine and valine and the mixed ones are isoleucine threonine tyrosine and phenylalanine now one of the reasons that this is so hard to memorize is because these amino acids fall into other categories that we've already discussed right some of these are essential obviously other ones are going to be non-essential some are basic so you you get the point it's hard to memorize what is what so i did my best to break this down with a mnemonic for you and it's kind of silly but if you really want to dig for that 260 on usmle or that 600 plus on complex then it's worth committing this to memory so when i think of the categories i just think of the different types of diets right so a ketogenic diet or a keto diet you'll eat lamb and liver okay in a glucogenic diet you'll eat honey mango and vanilla so lamb and liver l l for leucine and lysine and in a glucogenic diet honey mango vanilla hmv for histidine methionine and valine so kind of stupid i know but if you really want to be a gunner and get those points then anything you can do to simplify these concepts is very important i don't have a mnemonic for the mix type you'll just have to memorize that if you want to get a 270 but otherwise if you just know ketogenic and glucogenic you you've probably got a good grasp on this and you'll be able to get most of the questions that they throw at you in terms of these categories now let's change gears and talk about the amino acid derivatives so the big first part of the lecture was understanding which amino acids fall into which categories and that's definitely high yield this is also extremely high yield and this is where we're going to spend the rest of today's video the rest of this dirty biochemistry video on amino acids will be fully focused on telling you what are the derivatives of all of these different amino acids and because there are you know a lot of different amino acid derivatives this is a very high yield topic because these oftentimes get confused so we're going to spend a little bit of time on this so let's start with phenylalanine so if you remember from the previous video in the dirty biochemistry series we talked about the catecholamines and just to remind you this is what we talked about in that video so phenylalanine goes to tyrosine which then can generate dopa and from dopa in order you get dopamine norepinephrine and epinephrine but don't overlook the fact that you're starting with amino acids so phenylalanine starts this off which gets converted to tyrosine and only then can you go downstream to form your catecholamines so right off the bat we're going to use this chart phenylalanine and tyrosine's derivatives include dopamine norepinephrine and epinephrine aka the catecholamines you should already be familiar with that from the previous video but just for completeness sake here we are the next one that we're going to talk about is tryptophan now tryptophan can actually be converted into two different derivatives one is niacin and the other is serotonin and i'm gonna fill in the cofactors here shown in green vitamin b2 and vitamin b6 driving tryptophan toward niacin and niacin actually goes on to form nad plus and nadp plus you should sort of be familiar with that from earlier discussions in the dirty biochemistry series but if not here you are now on the serotonin side the cofactors are bh4 and b6 and then serotonin can actually be converted into melatonin so the reason that this is high yield is because all of this starts with tryptophan so you can't make melatonin from serotonin unless you have tryptophan first and you can't make nad plus an nadp plus unless you make niacin and before niacin you need tryptophan so tryptophan is an amino acid that gives rise to all of this stuff now there's a very high yield disease that occurs if you have a problem with tryptophan and if you knock out the ability to resorb tryptophan you get what's called hearten up disease so shown here on the slide we've knocked out the ability to have tryptophan therefore you get heart knob disease now heart enough disease is caused by decreased resorption of neutral amino acids and predominantly this is tryptophan and this is decreased resorption in the proximal tubule of the kidney so because tryptophan is knocked out again look at the slide here you cannot form niacin from tryptophan because if you have no tryptophan then you can't go to the left side of this flow diagram and form niacin so the inheritance here of heartening disease this is an autosomal recessive disease where do where because of decreased resorption of tryptophan you can't form niacin so not surprisingly the symptoms are going to be of a niacin deficiency and niacin deficiency you should know is termed pellagra or the 3ds diarrhea dementia and dermatitis now additionally in heart disease you see symptoms like ataxia and failure to thrive early in life again this is the part of the diagram i've taken half of it that shows tryptophan being knocked out which means you cannot form niacin and you cannot form nad plus and nadp plus so what are the findings well the findings are decreased levels of tryptophan decreased levels of niacin because you cannot form niacin from tryptophan and an increase of urine neutral amino acids since you can't resorb them in the proximal tubule of the kidney they stay in the urine so you see an increased level of urinary neutral amino acids specifically urinary tryptophan but the serum levels of tryptophan and niacin are all decreased and you have the sequelae or the symptoms of pellagra which is niacin deficiency now the treatment here is going to be nicotinic acid and the reason that this is the treatment is because nicotinic acid is the precursor to nad plus and nadp plus so it's thought that if you can't make niacin and therefore you can't convert niacin to nad plus and nadp plus as you normally would then the way to do it is to give them nicotinic acid which in and of itself is a precursor to those end products and you generate them that way now the reason that heart knob disease is so high yield in addition to everything that i've already mentioned is because medical students see dermatitis dementia the 3ds and they immediately jump to just niacin deficiency but if you see heart dip disease or any description of it such as decreased resorption in the proximal tubule of the kidney that's actually another possible scenario in causing pellagra so make sure you keep that in mind when you see diarrhea dementia and dermatitis okay if you see those symptoms it's not always just a pure niacin deficiency sometimes it's because you can't resorb tryptophan that is why hearten up disease is so high yield so let's update our chart we already talked about where the catecholamines come from and now tryptophan gives rise to niacin nad plus and nadp plus serotonin and melatonin now those are the two highest yields but there are some other amino acids that you definitely need to know their derivatives so we're going to include all of them on this slide the first is histidine histidine goes to histamine and it uses vitamin b6 as a cofactor this one's super easy to remember because histidine sounds exactly like histamine so really not that difficult to memorize glycine another amino acid this goes to porphyrin and vitamin b6 is the cofactor here and of course porphyrin is used to generate heme if you've done a little bit of your hematology section you probably already know that but for completeness sake glycine forms porphyrin and then heme secondarily now glutamate forms two end products and these are very high glutamate can go to gaba using a cofactor of vitamin b6 or it can glo go to glutathione we'll talk about this in just a little bit but this one's not terribly difficult to memorize because it is all the letter g and the last one that we're going to talk about is arginine now arginine is the most complex of any of the amino acids that have derivatives on this particular slide and that's because arginine can form three different end products so three different things can be derived from arginine and they are creatine urea and nitric oxide now in forming nitric oxide the cofactor bh4 is used but arginine is the most complex obviously because you're forming three different derivatives now how do you remember all this crap well my way of doing it is looking at the letters so histidine and histamine both have h they also sound nearly identical glycine and porphyrin both have y's in their name so the amino acid with y forms the only derivative that you need to know with a y porphyrin glycine for fearin glycine they both have the letter y in them glutamate goes to gaba and glutathione obviously it's all the letter g and then arginine forms creatine urea and nitric oxide i really don't have a good way of memorizing that but there you have it so if we update our chart here's all of the amino acids that you need to know and all of their derivatives the last category that i want to talk about are the branched amino acids now the branched amino acids are isoleucine leucine and valine now normally branched amino acids get a lot of hype in the news because uh people think that the more branched chain amino acids that they that they put into their body the bigger their muscles will be when they build them up so classically bodybuilders will take what are called bcaas branch chain amino acids because there's this thought that if they're branched they have a greater surface area and contribute to more muscle density now the you know the verdict's not really out on that just yet despite what you hear on bodybuilding forums but under normal circumstances the branch chain amino acids are broken down by an enzyme called branched chain alpha keto acid dehydrogenase and there's a disease that you can uh manifest if you knock out this enzyme and that is referred to as maple syrup urine disease and i kid you not that's literally the name of this disease so if you don't have branched chain alpha keto acid dehydrogenase for whatever reason you get maple syrup urine disease now i want to pause for one second the breakdown of isoleucine leucine and valine into their breakdown products it's it's not important for the purpose of boards to know what those breakdown products are so just know generally speaking that branch chain amino acids get broken down into their end products by the enzyme branch chain alpha keto acid dehydrogenase and when you knock out that enzyme you get maple syrup urine disease now let's talk about that disease it's extremely high yield so maple syrup urine disease again the pathophysiology is you don't have branch chain alpha ketoacid dehydrogenase so i've literally copy and pasted the picture of the enzyme with the knockout from the previous slide so now let's talk about the findings and the inheritance pattern so the findings are obviously there's going to be an increase in branch chain amino acids because if you can't break them down into their end products because the enzyme that normally does that is missing then you have a build up of these branched chain amino acids now you're also especially going to get a buildup of leucine now we talked about isoleucine leucine and valine as being the three branched chain amino acids but for whatever reason it seems that leucine tends to build up the most so remember that because if you see that finding on an exam then they're hinting at the branch chain amino acids building up uh as far as the inheritance goes this is an autosomal recessive disease process now what's important to know about maple syrup urine disease well obviously you need to know what the three branched chain amino acids are you need to know the name of the enzyme that get gets knocked out but the symptoms are definitely the highest yield so the reason that it's called maple syrup urine disease is because the urine is said to have this classic syrup smell to it so if you see syrup or maple or anything that sounds like you'd put it on pancakes but in fact they're smelling your urine instead the answer is maple syrup urine disease other symptoms that you'll see is intellectual disability and poor po intake or poor oral intake now how do we bundle all of this information into one high yield mnemonic well that's where dirty biochemistry comes into play my mnemonic is i love vermont maple syrup can i have a sip i love vermont tells you the three branch chain amino acids i for isoleucine l for leucine and v for valene maple syrup tells you that you're talking about maple syrup urine disease of course and may i have a sip or can i have a sip s-i-p and sip for syrup smelling urine intellectual disability and poor oral intake so those are the hallmark symptoms of maple syrup urine disease now that's it for this video i know that it was a lot of information but in conclusion or to summarize briefly you need to know the categories of the amino acids what's acidic what's basic what's essential non-essential what's ketogenic glucogenic or mixed and what is branched you need to know all of the high-yield derivatives from all of the important amino acids and especially pay attention to tryptophan and the possibility of developing heartening disease also pay special attention to the branched amino acids i l and v isoleucine leucine and valine and the possibility of seeing maple syrup urine disease if you can understand everything i just rapidly summarized then you're in excellent shape for amino acids