Enzyme Classification - Video Tutorials & Practice Problems

Common Naming Concept 1

Now, when it comes to the common naming of enzymes, we're going to say that unlike other compounds, enzymes are named based on their function rather than their structure. And we're gonna say that we modify the ending of the substrate name by adding ace. So a se to the end and our naming convention will be the substrate and then the modifier is us just changing the ending to ace. So just remember, enzymes are a bit unique. We're looking at how they function rather than their structure in terms of giving their common name.

Common Naming Example 1

In this example question, it says if kin a polysaccharide represents the substrate and a catalyzed reaction using a common rule, determine the name of its enzyme. All right. So king here represents our substrate structure. And now we're gonna talk about the enzyme. Remember when it comes to naming the enzyme, all we do is we modify the end by adding ace. So here we have kitten and then we would add ace to the end. So the name of its enzyme would be kinase. If we look at our options, this would be A B. So here the enzyme for kitten A polysaccharide would be kinase.

Systematic Naming Concept 2

Now, when it comes to the systematic naming of enzymes, we're gonna say in this case, for enzymes, the substrate attached and the type of catalyzes reaction can also determine the name under this system of naming. We're gonna use a naming convention of substrate, followed by the enzyme class. Later on, we'll learn about the different classes of enzymes and catalyze reactions and how those give us the overall systematic name for any given enzyme. All right. So just keep this in mind as we investigate how to name enzymes under this type of rule.

Systematic Naming Example 2

So in this example, question, it says hydro tase is a class of enzyme that catalyzes the addition of water to a molecule. What will be the name of the enzyme used in the following reaction? So if we take a look at this reaction, we have nlk A which is this structure here, we're utilizing an enzyme. And if we look, we had initially this double bond here between the two carbons, remember, carbon wants to make four bonds. So there's a hydrogen here and a hydrogen here that's invisible. If we look over here, those two carbons still have their hydrogens, but they have gained a water. They've gained, this carbon is gained in oh and this carbon here has gained in h that's the addition of water. The addition of water has also removed the pi bond, the double bond that we had initially in our reactant. So remember we're talking about systematic naming of an enzyme and the naming convention is the substrate, the substrate name, our substrate is our reactant. So this would be in the name. So B and D are out and then we would add the class of enzyme that's being used in this case, it's a hydro tase. So the name would be N Alcoa hydras. This would be the enzyme that has allowed us to add water to our substrate reactant. So here, our answer would be option C A doesn't work because we didn't talk about de hydra tase here. And D usually means that we're doing the opposite where we're having the removal of water, which is not what's going on here. Our reactant is gaining water, not removing water. So again, our answer would be option. C.

Six Main Classifications Concept 3

In this section, we'll talk about the six main classifications of our enzyme classes. Now, enzymes can be divided into six main classes based on the type of reaction catalyzed. And we're gonna say here that classes are further divided into subclasses based on the type of substrate. So here we have uh a majority of the name for the six classes of enzymes. We're just missing the first letter. So how do we remember what those first letters are? Well, here we're going to say what do enzymes do? Well, enzymes help speed up the rate of the reaction by lowering the energy of activation. They help reactions get over the hill. The hill representing that energy of activation that hill that we have to traverse or get over to become products. So over the hill o so this is oxido ducts, the transfer races and then hill, these are hydro lass summer races, li aes and ligas. So these are your different types of enzymes. The six classes of enzymes that we'll investigate. Remember, some of them can be further broken down into subclasses based on the substrate that's involved. So keep this in mind while we're talking about the different classes of enzymes that exist.

Oxidoreductases Concept 4

Now the first class of enzymes we'll talk about are are oxido duc tases. Now, here they catalyze oxidation reduction or redox reactions by transferring electrons between molecules. Now, we've talked about redox reactions before in the past. So remember in this case, oxidation means the loss of hydrogen or the gaining of oxygen and reduction we're gonna say is the opposite. It's the gaining of hydrogen. And here you could lose more than one hydrogen gain more than one oxygen. Here, you could do the same thing here for reduction. If you gain more than one hydrogen and lose more than one oxygen. Now, we have subclasses to this particular class of enzymes. The subclasses are oxidase and reductase oxidase. From the name they oxidize a substance for duct tastes, they reduce a substance. If we take a look here at this reaction, we have a glucose molecule and we are using the enzyme glucose oxidase. This is written in the systematic name where we have the substrate name, which is glucose followed by the class or subclass of enzyme. Here, oxidase means that we're going to oxidize a glucose. So what happens here is we have an alcohol in essence in alcohol here. And remember when we oxidize an alcohol, we're trying to make a carbon group. So this carbon now is double bonded to the oxygen. It's an oxidation because what has it happened? Well, we're gonna say it's an oxidation because carbon has lost its h oxygen has lost its h. So this is occurring at the same time, carbon and oxygen are forming a double bond with each other. So carbon is gaining in essence an oxygen by forming an additional bond to it. This is also telling me oxidation is occurring. So we've gone from glucose here r starting material. We've used our enzyme to oxidize it and we created glucon on 15 lactone. You don't need to know how to name this. This is just a product that forms. And then also as a byproduct's made hydrogen peroxide, the key takeaway from here is knowing that glucose is our substrate and knowing that glucose oxidase is the systematic name for our enzyme being used to oxidize the glucose. That's what we take away from this. And then we have to remember in the overall picture that this represents an oxido reductase type of reaction, right. So keep that in mind when investigating this first class of enzymes.

Oxidoreductases Example 3

Here it says which of the following is an indicator that a reaction is cat lives by an oxido red duc tase. So remember this is the class of enzymes dealing with redox reactions. So we have reduction which could represent the gaining of hydrogen or the loss of oxygens or we can have oxidation or it's the gaining of oxygens or the loss of hydrogens. So here let's look, loss of a function group. No, that's not involved in redox, loss of water. Still not involved in redox, loss of hydrogen or loss of a substance. Substance is too vague. Loss of what kind of substance C is the right answer. Loss of a hydrogen. Remember loss of a hydrogen in this case would be an example of oxidation and in subclasses that is oxidation that help us, right? So here we say the answer would be option C.

Transferases Concept 5

In this video, we'll take a look at the second class of enzymes. Here we have our transfer races. Now, here they catalyze a transfer of functional groups between molecules and this one has subclasses, we have transaminases and we have kinas. So transaminase, this is just the transfer of an amino group. So a nitrogen containing group and knees deals with the transfer of a boss faith group. If we take a look here at our reaction, we have glucose molecule as our substrate and here we have a TP. Remember that's just energy here, we're gonna have our hexokinase involved kinase ends the name. So it's gonna deal with the transferring of a phosphate group. Now what happens here is that A TP has some phosphate groups. This enzyme is gonna help us take one of them away and it's gonna get transferred. So the H here is gonna be removed. So that one of the phosphate groups from A TP can attach to this structure here. So when we look over to the product side, we no longer have glucose, we have glucose six phosphate here. The age has been replaced with this phosphate group. A TP is no longer a TP because it's lost one of its phosphate. So now it's AD P and the H that was replaced is just hanging around here as an H plus. So the key takeaway from this is being able to recognize what has been transferred. We have a glucose molecule, the H from glucose has been transferred out for phosphate. That is a key giveaway that we're dealing with a subclass of enzymes called kinas, right. So just remember transferase is just an enzyme that helps us to transfer functional groups uh between molecules and kinas help us to transfer phosphate groups.

Transferases Example 4

Here, it says, identify the type of enzyme subclass from the phone reaction. If we take a look here, we have our beginning reactants and we have an unknown enzyme which is a question mark and we're making these products. If we look this chain here is similar to this chain here and this chain here, which is larger in appearance is this chain here. But what's the difference? Well, here, we didn't have a carbonel group here, but now we do and we're gonna say that we didn't have an NH three group here. We had a carbon group there instead. So what happens is that this amino group got transferred over and this carbon got transferred over. They kind of swapped places. We have the transferring of an amino group between molecules. And what subclass of enzymes are gonna help us do that. We're gonna say that is a trans amen. So we'd say our transaminase is a subclass of enzymes that was used to transfer our amino group from one molecule to another molecule.

Hydrolases Concept 6

In this video, we're gonna talk about the third class of enzymes and that is hydrolysis. Now, in these types of enzymes, we catalyze hydrolysis reactions. So basically it breaks bonds by adding water. And with this type of class of enzymes, we have subclasses. And one important thing to take away from this is that although these are hydro lases, none of them have hydro within their name. Ok. So that makes it a little bit more tricky in terms of remembering, but all of them will utilize water in order to break bonds. For the first one, we have lie pieces. We're gonna say they hydrolyze ester bonds in lipids. Next, we have proteases, they hydrolyze proteins into peptides and amino acids. So they're breaking down proteins into their less complex structures. Next, we have nucleus, they hydrolyze DNA and RN A into nucleic nucleic acids. And then finally, we have here phosphatases, they hydrolyze phosphate ester bonds. So here if we take a look, we have this polypeptide and we're gonna utilize this protease. Remember that helps to hydrolyze proteins into peptides and amino acids. So it's gonna break this polypeptide into smaller chunks and we're gonna be using the enzyme to help us cut or cleave this font here. If we come over here, what has occurred? Well, we can see that we have severed this bond here and this carbon here is this carbon here and it's gained in O minus. And then this nitrogen here is this nitrogen here. It's gained two hydrogens. So what have we gained? We gained two hydrogens plus one oxygen. So we've added water to our polypeptide. So we use water to cut the bond and split into two pieces, right? So here, this is a great example of one of our subclasses of hydrolysis. Remember there's a lot of subclasses within this class of enzymes, but none of them have hydro within their name.

Hydrolases Example 5

Here in this example, question it says which subclass of hydrolysis, it is responsible for breakdown of triglycerides and other lipids into free fatty acids and glycerol. Right? So we're seeing a lot of terms here. What's the key word leopards? And we know when it comes to lipids, the subclass of hydro lases that we would utilize are our lie pas right? Lie pace, lipid lip and lip. That's a key giveaway. What's going on here? Remember we're changing the end of the substrate name to ace, right? So lipid, we change the ending to ace, which is how we came up with lie pace, right? So just keep that in mind when taking a look at this particular example, question, we uh use lie paces or or light pace in order to cut these lipids into smaller fragments or smaller molecules.

Isomerases Concept 7

In this video, we're gonna take a look at our fourth class of enzymes our isomer ases. So here we're gonna say we have to catalyze the c we catalyze the creation of an isomer by shifting functional groups to a different location within the same molecule. So in this reaction, we have dihydroxy acetone phosphate and we're using an isomerase to it to help us to create glyceraldehyde three phosphate. What has happened here? Well, we have this hydroxyl group which was at the end and it got shifted over to our next carbon next door or adjacent carbon. And at the same time, we had this carbon deal here and it's now at the end. So they have shifted positions. This is an example of an isomerase. Also notice that when it comes to this class of enzymes, we don't have subclasses. So, all right. So we're just gonna have an isomerase. It helps to create different isomers by moving functional groups to different locations within the same molecule.

Isomerases Example 6

Which of the following represents a reaction of an isomerase. All right. So if we take a look at the first one, what's occurring here is that we have this hydrogen getting replaced by this phosphate group. So we're, we're moving in a phosphate group from a TP in order to do this, we're transferring a phosphate group. So this is a kinase kinase doesn't belong to the class of called isomer. So this would not work for the next one. It may look like we've done something to our starting material to create this other one. But we really haven't. If we were to number this in order to name it, we'd start off from this end 12345 here, this would be two palone. And again, we've discussed naming keytones in earlier chapters. So it's gonna be important that you were able to identify that these are the same molecule here would be 12345. This is also two pino nothing has been done to this molecule. It's just been flipped and turned around to make it look like something has occurred. So this would be nothing for the next one. We have lost hydrogens here. In order to make a pi bond here, we can say that this is a form of oxidation. We've lost hydrogen. So we could say maybe an oxidase got involved here, some something that helped us to lose hydrogen. And we know that that is not an isomerase, we didn't transfer uh uh make an isomer by moving things around. So this would not work now by process of elimination. D is the answer. But why remember an isomerase is making an isomer, an isomer has the same formula but different connections. And if we were to look at these two and add up all the carbons, all the hydrogens, all the oxygens, they both would have the same exact formula, but they look different. That's because they're isomers of each other. So this one was a bit tricky but these are answer. OK. It may have been hard to see. But again, isomers same molecular formula, different connections in this case. And because of that, because we, we, we have isomers, that means an isomerase had to have been used, right. So again, our answer would be D.

Lyases Concept 8

In this video, we'll take a look at the fifth class of enzymes are lias. Now, here they catalyze the addition or removal a functional groups without hydrolysis or redox reactions. Now, here we're gonna have the additional removal of groups are gonna help to break and create creates double bonds respectively. With this type of enzyme class, we have subclasses. So here are subclasses are de hydro gasses, they help to remove water. Since hydro tases help to add water, we have D ainas, these help to remove amino groups. So NH three and then decarboxylase. This one's not as easy to see, but decarboxylate deals with the removal of CO2. If we take a look at our two reactions, we start out with fumarate here and we're gonna use pumera or hydroa which means we're gonna add water or adding water to this pie bod. So here in order to add to those two carbons, we have to destroy the Pyon, remove it. And here's the water we added in the form of oh and h below that, we have a tyro and to this tyrosine, we're using tyro decarboxylate. Remember decarboxylate means a loss of CO2. The CO2 that we're gonna lose is this one? Here we lose that CO2. So now that carbon here has lost that CO2, it's gained a hydrogen to remake the loss because remember, carbon must make four bonds and here goes the CO2 that was lost. So again, remember here we're dealing with Li Aes and there are quite a few subclasses when it comes to this particular class of enzymes. So keep that in mind, What exactly are we adding or removing, to properly identify the subclass of enzyme?

Lyases Example 7

Here, this question. It says which of the following subclasses of enzymes responsible for catalyzer reactions where a molecule undergoes non hydrolytic cleavage forming multiple molecules without addition or removal of water. All right. So a bulk of this is describing our lias as our subclass of enzyme out of the options. Given that mean our answers, either B or C here, phosphatases don't work and transaminases don't work. They're not in this class of enzymes, but here's the key thing they're saying without the addition or removal of water dehydrate, this deals with the removal of water. So it couldn't be seen. So by process of elimination, it has to be option B deaminase has to do with the removal of an amino group NH three. They never said anything about removal of NH three. Here they're talking about without the removal of water that eliminates option C but not option B. So again, option B would be our final answer.

Ligases Concept 9

In this video, we'll talk about the sixth class of enzymes are ligas. Now, here they catalyze covalent bonding of two molecules together with the use of a TP. So energy is required here. Now, we have two subclasses that belong to this class of enzymes. They are our synthetase and then our carboxylase. So synthetase form a bond between two molecules carboxylase. They form a bond between specifically CO2 and another molecule. If we take a look here, we have pyruvate and next to pyruvate, we have CO2, the required a TP and then our ligase in the form of pyruvate carboxylase. So carboxylase means we want to add co2 to our pyruvate molecule. So this ch three is gonna have CO2 added to it to do this. We have to sacrifice one hydrogen from the carbon because carbon can only make up to four bonds doing this transforms pyruvate into oxy acetate. And we're gonna say here, we also create what ad P as a by-product because we had to use a phosphate from A TP. And then we also have our acid here. That's form plus H plus. So again, this represents a carboxylase because we had the joining of a carbon dioxide molecule with pyruvate another molecule, right. So keep this in mind when looking at this six class of enzymes and the two subclasses that belong to it.

Ligases Example 8

So in this example, question, it says during protein synthesis, blank enzyme catalyzes the attachment of an amino acid to a corresponding transfer RN A molecule through an ester bond. All right. So here we're joining two molecules to each other. So we know we're dealing with the li gates and we're gonna say that it could either be a synthese or a carboxylase. Can't be a carboxylase because they never talked about joining carbon dioxide to either one of these molecules. So it has to be sy the face. So we're gonna say here our synthese enzyme is what's catalyzing the joining of these two molecules within this particular example. Question.

Summary of 6 Enzyme Classes Concept 10

So in this video, let's do a rundown of our six classes of enzymes. All right. So here we have our enzyme classes, we have our reaction that's catalyzed. And then we have the description involved. So let's go down this list. So for the 1st 10 oxido reductase is. So here we have molecule A and molecule B, if we look on the other side, we can see that there are changes that have occurred. We can see that A has lost its two electrons and hand them over here to bh three. So we have the transferring of electrons from A to B A has lost its electrons. So here we'd say that A is being oxidized B has gained those electrons. So we'd say that it is being reduced. So we're looking at a redox reaction here. So here we're gonna say the description is redos reaction via transfer of electrons. Next, we have T transfer A molecule A has this group here that's extending from it. And then if we look that group has transferred from A to B, now on the product side, B has that extending group. So here this deals with the transfer of functional groups. Next, we're gonna have h hydrolysis or hydrolase. Here we have A plus B being connected together by this bond. And we have water, water is gonna be used to cut or cleave that bond in the process. A got hydrogen and B got oh water has been added in order to break that bond. So here the description is we break bonds by adding water. Next, we have I isomer ASIS. So a here on that molecule oh is on the right side of it. And then what's happened, it's been shifted over to the other side. Now we just have to assume that A is not a symmetrical molecule that there's differences from the right side and the left side. So that when oh transfers to the other side, it creates a brand new structure. So here we're gonna have the rear it rearranges atoms within a molecule to create isomers. Remember isomers have the same formula, but here they're gonna have different connections. Next, we have a lia or lias is. So we have A and B connected here that is severed and now we have A and B separate. Here, we're gonna say the description is we have it breaks or forms bonds without redox reaction, redox reactions or water. And then finally, we have ligase or ligas A plus B require a TP in order to form a bond with each other on the product side. So here we use energy to go violently join molecules together, right. So this gives us a good rundown or summary of our six classes of enzymes.

Which of the following could be the possible name of enzyme that involves the transference of a phosphate group between substrates?

• A. Tyrosine Kinase 
• B. Cysteine Isomerase 
• C. Cellulase
• D. Glutamate deaminase

Which of the following enzyme name and function is incorrectly matched?

• A. Glucose Oxidase – Catalyzes the oxidation of the glucose molecule.
• B. Sucrase – Catalyzes the hydrolysis of sucrose. 
• C. Deaminase – Catalyzes the addition of NH₃ to a substrate. 
• D. Pepsin – Catalyzes the digestion of proteins from food that is consumed.

Which of the following statements is true of ethanal reductase?

• A. It represents a hydrolase that acts upon the ethanol substrate to oxidize it. 
• B. It represents an oxidoreductase that acts upon the ethanal substrate to oxidize it.
• C. It represents a lyase that acts upon the ethanal enzyme to reduce it. 
• D. It represents an oxidoreductase that acts upon the ethanal substrate to reduce it. 

Identify the class and subclass of an enzyme that catalyzes the following reaction.

• A. Lyase, Hydratase
• B. Hydrolase, Protease
• C. Lyase, Dehydratase
• D. Hydrolase, Nuclease

Which of the following catalyzes the given reaction involving a triglyceride?

• A. reductase
• B. lipase
• C. kinase
• D. decarboxylase