we're going to very quickly look at the different classes of enzymes and also molecules and co-actors that are called co-enzymes so we've got a number of different enzyme classes and we can um really group them up into six different groups first is our oxido reductases and as you may guess by the oxy and the reduct these are going to do oxidation reduction reactions often times nadh might be a co-actor that will be used in these reactions as we'll see on the next slide transferases are going to catalyze the transfer of functional groups from one molecule to another so we'll have a particular functional group on one molecule and we will now be converting that onto a different molecule hydrolases are going to catalyze hydrolytic cleavage Li Li liases are going to be able to remove or add groups to a double bond and we'll take a look at that on the next slide isomerases are going to involve intermolecular rearrangement so for example it could be going from a cyst to a trans Arrangement around a double bond ligases are going to join two molecules together and an important thing to remember is that most enzymes are going to be named for both their substrate and the type of reaction that they do so here's some examples of these enzymes and again there are many enzymes that fall within these types this is just illustrating one particular enzyme type so again our oxido reductases is going to do an oxidation reduction so an example enzyme would be alcohol dehydrogenase so we are going to be oxidizing this carbon it currently has two hydrogens on it and in the product it is now going to have two bonds to oxygen and only one bond to hydrogen so it has been oxidized nad+ is going to be our oxidizing agent and it in the process will be reduced to nadh so this is a great way to make nadh um and we will see nadh when we get into metabolism in future in future videos so our second type was the transfer a so we're going to be transferring a functional group from one molecule to another in this case hexokinase the transfer um the transferase reaction that we're doing is we're going to be transferring a phosphate group so this would be a phosphorilation enzyme so we've got on ATP this is adenine Tri phosphate so we're going to be transferring the phosphate from ATP to um glucose specifically to this oxygen and glucose so you can see we now have a phosphate group on that oxygen and our ATP addine triphosphate becomes a DP Adin diphosphate hydrolases are going to be breaking apart uh molecules so this is carboxy peptidase a um and so we are going to be cleaving this amid Bond so we're going to be adding water across that um and essentially this is a way of cleaving a polypeptide so we've got a polypeptide chain here and now we've got two shorter polypeptides in this case an amino acid we saw this enzyme in um earlier in the semester when we wanted to figure out what the C terminal amino acid um in a polypeptide chain was Elias in this case um we are going to be um decarboxylating this molecule so we're going to be taking pyruvate and we're going to be removing carbon dioxide from it uh so this Mo this enzyme is called pyruvate because the substrate is pyruvate decarboxylase because we are removing this carboxilate group from it and acet alahh would be our product along with carbon dioxide in this case we mentioned how isomerases are going to change a molecule from um for example from a Cy to a trans in this case malate we have a Cy molecule our hydrogen are on the same side of of the double bond we're going to isomerize it into Fumarate in which case our hydrogens are trans from each other otherwise the molecule remains unchanged aside from that isomerization and then liases are going to be joining two parts together so this would be the opposite reaction as our lias up here so in pyate DEC carboxilate we were taking pyat and removing a carbon dioxide in pyruvate carboxilate we're going to be taking pyruvate and we're going to be adding a carboxilate uh so we're going to add this carbon dioxide to this end carbon here so that goes through the some of the major classes of enzymes and the types of reactions that they do many enzymes will also need co-enzymes in order to function so a co-enzyme is going to be a nonprotein molecule that will help the enzyme with its function and it's usually associated with the active sight of the enzyme so if you have an enzyme and it has its co-enzyme we call that a Holo enzyme or a Hol enzyme depending on how you particularly want to pronounce it if you have the enzyme alone without the co-enzyme we call that an APO enzyme we can have two different classes of co-enzymes one is going to be our organic co-enzymes and you actually know these as vitamins so for ex for instance thiamine riboflavin niin Biotin and we'll see some more on the next slide whereas our inorganic co-enzymes we know those as our minerals so magnesium iron 2+ zinc 2+ manganese 2+ those all act as inorganic co-enzymes so these molecules are going to help the enzyme function if you have the APO enzyme for an enzyme that requires a co-enzyme it will not work in its APO form okay so here are some examples of some inorganic co-actors so iron copper zinc some enzymes that they work work in and the role that those metals are going to play I give you an example here using carboxy peptidase again because we've seen carboxy peptidase as an enzyme before its active site has a zinc in it that is coordinated to two histadine and a glut a glutamic acid or glutamate so what the zinc is going to do is it's going to activate a water molecule so what we mean by activate is it's going to um do it's going to bond to this oxygen that oxygen now is going to be more nucleophilic so it's going to be able to do a nucleophilic attack on this carbon um in the carbonal of our peptide so this green portion here is our peptide that we're trying to remove our C terminal amino acid from so it's going to be able to do a nucleophilic attack on this carbon um and because we've got this glutamic acid here it will take this hydrogen from water that helps um activate this oxygen as well um and now we've got a hydroxide which is a much better nucleophile than a water molecule that has added to that carbonal that zinc is going to help hydrog or help stabilize the formation of this oxygen here um and when the electrons from this oxygen come back down that's going to release the O here and the water uh will now be added across uh this nitrogen amid Bond here so we had an amid Bond this water molecule has now been added across it the O portion portion going to the carbonal and the hydrogen going to the nitrogen so all this was possible because the zinc in the active site was activating this water molecule and weakening the oxygen hydrogen bond allowing that oxygen to now be a better nucleophile um in this slide what we're going to see is that most of our vitamins are co-enzymes and what they're going to do is a variety of different reactions but all of these are involved in our metabolism and so metabolism is how we're going to get energy from our food sources so we will cover this later in our in our book but what I wanted you to realize is that all of these vitamins are necessary as co-actors for enzymes that allow you to get energy from your food