Now the first class of enzymes we'll talk about are our oxidoreductases. Here, they catalyze oxidation-reduction or redox reactions by transferring electrons between molecules. We've talked about redox reactions before. So remember, in this case, oxidation means the loss of hydrogen or the gaining of oxygen. And reduction, we're going to say is the opposite. It's the gaining of hydrogen, and you could lose more than one hydrogen, gain more than one oxygen. For reduction, you could gain more than one hydrogen and lose more than one oxygen. We have subclasses to this particular class of enzymes. The subclasses are oxidases and reductases. Oxidases, from the name, they oxidize a substance. Reductases, 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, the term 'oxidase' means that we're going to oxidize the glucose. What happens here is we have an alcohol, and remember, when we oxidize an alcohol, we're trying to make a carbonyl group. So, this carbon now is double-bonded to the oxygen. It's an oxidation because carbon has lost its hydrogen, and oxygen has formed a double bond with carbon. This indicates oxidation is occurring. We've gone from glucose, our starting material, used our enzyme to oxidize it, and created glucono delta-lactone. As a byproduct, we've made hydrogen peroxide. The key takeaway here is knowing that glucose is our substrate, and that glucose oxidase is the systematic name for our enzyme being used to oxidize the glucose. This is what we take away. And we have to remember that this represents an oxidoreductase type of reaction. So, keep that in mind when investigating this first class of enzymes.