What is PEP?

Prepare for the Microbial Metabolism Test. Utilize flashcards and multiple choice questions with helpful hints and detailed explanations. Ace your test with ease!

PEP is phosphoenolpyruvate, a high-energy phosphorylated metabolite used to transfer a phosphate to ADP in metabolism. In glycolysis, the enzyme pyruvate kinase takes the phosphate from PEP and adds it to ADP, forming ATP and pyruvate in a substrate-level phosphorylation step. The energy is released because the phosphate is attached to an enol phosphate; once transferred, PEP becomes pyruvate, which rapidly tautomerizes to the more stable keto form, helping pull the reaction forward. This makes PEP a key energy-rich donor in metabolism. It isn’t a membrane potential generated by ions, it isn’t an enzyme itself, and it isn’t a cytoskeletal protein.