What is produced along with ATP when phosphoenolpyruvate (PEP) is converted to pyruvate?

When phosphoenolpyruvate (PEP) is converted to pyruvate, the process involves the enzyme pyruvate kinase in the glycolytic pathway. This reaction is a substrate-level phosphorylation event, where a phosphate group is transferred from PEP to ADP, resulting in the production of ATP and pyruvate.

In this particular reaction, NADH is not produced because it is not involved in the conversion of PEP to pyruvate—the primary focus here is the transfer of high-energy phosphate. FADH2 is also not produced since that cofactor is typically involved in different metabolic pathways, particularly those concerning the oxidative phosphorylation in the mitochondria. CO2 is not released in this reaction; it is produced mainly during the decarboxylation of pyruvate in the conversion to acetyl-CoA. Water is also not a direct product of this reaction, as it plays different roles in other biochemical reactions but is not formed during the transformation of PEP to pyruvate.

Therefore, the correct and relevant product along with ATP from the conversion of PEP to pyruvate is indeed pyruvate itself, with the consideration that NADH is often part of other reactions in cellular metabolism but does not directly accompany