Pyruvate carboxylase, the first step of hepatic gluconeogenesis, is allosterically activated by:

• A Acetyl-CoA, indicating adequate fat oxidation and surplus carbon for gluconeogenesis ✓
• B AMP, indicating energy depletion
• C Oxaloacetate, the product of its own reaction
• D NADH, indicating reducing equivalents for gluconeogenesis

Explanation

Pyruvate carboxylase converts pyruvate + CO2 + ATP to oxaloacetate in the mitochondrial matrix; it is allosterically activated by acetyl-CoA, which signals that fat oxidation is proceeding and the TCA cycle is saturated — conditions favouring gluconeogenesis over pyruvate entry into the TCA cycle. AMP activates AMPK (which inhibits gluconeogenesis). Oxaloacetate does not feedback-activate pyruvate carboxylase.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.