Many reactions we will see involve redox reactions catalyzed by dehydrogenases. Now, these are just a subclass of oxidoreductases. And when it comes to dehydrogenases, they require coenzymes to become active. Now, here we're going to talk about different types of coenzymes, and we're going to say the most common coenzymes we will need to know are the following. So the first one we know is ATP. ATP here is composed of 3 things. It's composed of our adenine nitrogenous base, our ribose sugar, and then our 3 phosphates. Next, we have NAD+, and think of the next 3 as different variations of the ADP molecule. So all of them have this ADP portion which is adenosine diphosphate and connected to it is this new portion to make it something different. Here for NAD+, after the adenosine diphosphate, we have our CH2 group connected to a ribosugar again. And then we have this nitrogen portion which is nicotinamide. Next, we have FAD. FAD, we have our Adenosine Diphosphate portion. We have our Ribotol, which is an alcohol portion. And then flavin. Now, remember that these two things must be involved in some way within the Citric Acid Cycle. When we talked about food catabolism, we talked about the 3rd step involving these 2 in the production of NADH and FADH2. And then finally, we have Coenzyme A which has the ADP portion again, the pantothenic acid, and then we have aminoethanethiol portion. You may also notice that these are in some type of mustard color because those are the sites of some of the redox reactions we're going to see. Because remember, we said that these are involved in redox reactions, those are the sites where it will occur. Now, there are other coenzymes that are important but their structures are too complex and beyond the scope of the course. So, it's less important to know what they look like. It's more important to know that they are also common types of coenzymes. And those would be the coenzymes of B12 and Q. Right? So these would represent our most common types of coenzymes.
Intro to Coenzymes - Online Tutor, Practice Problems & Exam Prep
Intro to Coenzymes Concept 1
Video transcript
Intro to Coenzymes Example 1
Video transcript
In this example, we have to identify the substrate, coenzyme, and product for the following reaction which involves the enzyme Succinate dehydrogenase. Alright. So, we're going to say here, Succinate would have to be our substrate because we said earlier that one of our common coenzymes is FAD. The question doesn't ask this, but we know that this ends with ACE, which represents our enzyme. The enzyme and this coenzyme put together, make it active in order to change our substrate succinate into fumarate. Fumarate here would have to be our product. In this process, we've created FADH2. So FAD has been transformed into FADH2. Here, this is just another product but not the main product that we're concerned with. So, here again, Succinate will be our substrate. FAD is one of our common coenzymes. We have our enzyme that works in conjunction with it to create fumarate, which is our product.
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