Let us continue our step by step discussion of glycolysis. Remember that, although here are several purposes for this discussion in the context of MCAT preparation, one of these purposes is NOT for you to worry about memorizing everything.

Where we last left off, BPG had phosphorylated ADP forming 3-phosphoglycerate and ATP. Subsequently, then phosphoryl shift occurred converting 3-phosphoglycerate to 2-phosphoglycerate. The next very interesting step is the action of the enzyme enolase upon 2-phosphoglycerate to form phosphoenolpyruvate. To make this converation, enolase carries out the dehydration upon the C-3 hydroxyl group, leading to the formation of a double bond, which markedly increases the phosphoryl group transfer potential of the molecule. Why is that? The high negative free energy of the phosphate transfer potential of phosphoenolpyruvate arises because of the subsequent enol to ketone conversion. Phosphorylation of ADP by PEP is going to form the enolate of pyruvate which quickly converts to pyruvate.