Final answer:
High alanine can inhibit pyruvate kinase activity when there is enough energy and alanine is abundant. Pyruvate kinase is regulated through phosphorylation and is also affected by fructose-1,6-bisphosphate and ATP. It plays a crucial role in the last step of glycolysis.
Step-by-step explanation:
Pyruvate kinase plays a crucial role in the last step of glycolysis, where it catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate, generating ATP. High levels of alanine can inhibit the activity of pyruvate kinase when no more energy is needed and alanine is abundant. Additionally, fructose-1,6-bisphosphate levels increase the enzyme's activity. The regulation of pyruvate kinase also involves phosphorylation by a kinase, resulting in a less-active enzyme, and dephosphorylation by a phosphatase to reactivate it. ATP negatively regulates the enzyme's activity as well.