Which of the following enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvate? Now, this represents reaction 10 of glycolysis, which is a phosphate transfer reaction. We know that when we're transferring phosphate groups, that involves our class of enzymes known as kinases. So if we take a look, we have a kinase here and we have a kinase here. This couldn't be the answer to pyruvate dehydrogenase because that deals more with oxidation, not the transferring of a phosphate group. And then pyruvate carboxylate, that's just talking about our pyruvate group with the carboxylate group that's been deprotonated, has an O negative. And remember, we're looking for the enzyme and it doesn't end with the name of an enzyme as well. Now here it's either C or D.
Now phosphoenolpyruvate carboxykinase, this deals with the carboxylation of PEP. But remember, we're not trying to add a carboxylic acid group to PEP, we're trying to lose a phosphate group from PEP in order to change it into Pyruvate. This happens not with option C as an enzyme but with option D. Pyruvate kinase is the enzyme of choice which will lead to the transferring of our phosphate group from PEP to ADP transforming it into ATP. While doing this, PEP is transformed into pyruvate. So option D would be our final answer.
