On the basis of the classification given in Section 22.2 decide to which group each of the follo

On the basis of the classification given in Section 22.2...

Key Concepts

Isomerases

Isomerases are enzymes that catalyze the rearrangement of atoms within molecules, changing them from one isomer to another without adding or removing atoms. They are essential for processes where molecules need to be converted into different structural forms, and they are categorized under EC Class 5.

Hydrolases

Hydrolases are enzymes that facilitate the cleavage of chemical bonds through the addition of water. This broad category, classified as EC Class 3, includes enzymes that break down complex molecules into simpler ones by hydrolysis, which is fundamental in many metabolic pathways.

Oxidoreductases

Oxidoreductases are responsible for oxidation-reduction (redox) reactions, where electrons are transferred between molecules. These enzymes, categorized under EC Class 1, play key roles in energy production, metabolic pathways, and maintaining the redox state within cells.

Lyases

Lyases are enzymes that catalyze the addition or removal of groups to form a double bond or break bonds without hydrolysis or oxidation. Classified under EC Class 4, lyases are important in processes such as the removal of ammonia or carbon dioxide from substrates, which helps in metabolic regulation and energy flow.

Enzyme Classification Systems

This concept involves organizing enzymes based on the reactions they catalyze. The most common system is the Enzyme Commission (EC) number classification, which divides enzymes into classes such as oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Understanding this system is crucial for categorizing enzyme functions and relating structure to activity.

Transcript

00:01 All right, so we're classifying four different types of enzyme reactions.

00:07 Okay.

00:08 And for a full list of your options, there's six different options for what each one of these could be.

00:14 You can see section 2 in your book.

00:19 There is a list, one through six of the different types.

00:22 We have oxidoreductase, transfereases, hydrolases, lyases, isomerases, ligases, or synthetases.

00:31 Are ligase and synthetase.

00:33 Those are the same kind of class.

00:35 There's also a chart.

00:36 Table 22 .1 has a chart that has some examples on it to help you kind of figure out who is who.

00:43 All right.

00:43 So our first one here that we're going to classify is phosphoglyceromyutase.

00:49 Okay.

00:49 And i've written out the reaction that goes with it that they're using as your example.

00:53 Now there's a couple things i want you to notice.

00:55 The first thing is from the reaction itself.

00:57 Okay, we're starting with our hydroxide.

01:01 We have a hydroxide, turning my pen back on, there we go.

01:07 We have a hydroxide down here underneath, and then this phosphorus group up top.

01:13 And in the product side, we've swapped them.

01:17 Okay, that's a form of transfer, okay, which makes this a transferase.

01:25 Okay, now transferases are used all over the place from, shuffling one type of molecule into another part of a cell, okay, to something like this where it's within the same molecule.

01:36 Okay.

01:37 Now, the term that can give you a heads up from the name is this mutase.

01:43 Okay, there's a few different endings that can be the transferases.

01:47 A mutase is specifically, think like mutate in a way, it's specifically this situation where you're moving something within the actual molecule itself.

01:59 So we're not physically transferring it from inside a cell to outside.

02:03 We're simply working with the same molecule and we're shifting things around within that molecule.

02:10 All right.

02:12 This is also called a intra -molecular group transfer.

02:20 Intra -molecular.

02:22 Intra means inside.

02:23 So inside the molecule group transfer.

02:27 That's what that mutase means.

02:29 All right.

02:31 So this first one is classified as a transfer ice.

02:35 Now i'll pause for a second to get our next one written up here.

02:41 All right.

02:41 So here's our next one drawn out.

02:43 This one is urea's.

02:44 Right.

02:45 And let's look at the reaction.

02:47 See if we can figure out what's happening.

02:49 Okay.

02:49 We're starting with one molecule.

02:51 Okay, this is actually urea.

02:54 Okay, it has two ammonia groups on either side.

02:57 With that co in it, that would actually make these amide groups.

03:00 Right? we're adding water to it and we're ending up.

03:03 Up with two ammonia's, nh3, and carbon dioxide.

03:08 All right, so let's try to think through what's happening here.

03:11 The nh2s must be coming off, okay, in order to make nh3.

03:16 So that means we must be breaking both of these bonds.

03:20 Okay.

03:21 And then nh2s are becoming nh3s.

03:25 So that means that a hydrogen must be joining each of those nitrogens.

03:35 All right.

03:36 And then what we have left here in the middle, the co, well, he became co2.

03:41 So he must have gotten the extra oxygen that came from the water.

03:45 All right.

03:45 So what's happening is we're breaking bonds and then water is getting added into the system.

03:50 Okay.

03:50 Water's getting broken up and added in different places to balance the charges out.

03:54 So you're making stable molecules.

03:57 That is the classic definition of a hydrolase.

04:04 Okay.

04:05 Hydrolases are enzymes that catalyze hydrolysis.

04:11 Catalyze hydrolysis.

04:13 Okay, and hydrolysis is when you break bonds and you add a water molecule in, whether it's breaking it up in this case where the hydrogens and the oxygens all came apart, or you're breaking it up into a h and an oh.

04:26 Okay, there's different combos.

04:28 This is going to be your hydrolase.

04:31 We'll pause again and get the next one up.

04:33 All right, now we've got part c, cessinate dehydrogenase.

04:40 All right, now let's try to see what's going on here.

04:42 We have a chain that we're starting with here, and we're adding something called fad or fad.

04:51 This is a co -enzyme, and the reaction specifically says that's its oxidized form.

04:57 Our product, it looks like we're creating a double bond.

05:01 And if i actually draw it where it is in the original one, this arrow here, that's where that double bond's going to be.

05:12 Okay, so we created a double bond, and then we have fad, and he's gained a couple hydrogen.

05:18 So now it's fadh2, and the subscript or the caption that goes with it is that's the co -enzyme in its reduced form...

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