Phosphoenolpyruvate shuttle ‐ transport of energy from mitochondria to cytosol

Abstract
Brown‐adipose tissue mitochondria of hamster and rat contain phosphoenolpyruvate carboxykinase (EC 4.1.1.32). In the presence of ketoglutarate and malate, phosphoenolpyruvate is formed and exported forms mitochondria. Phosphoenolpyruvate formation is inhibited by 1,2,3‐benzenetricarboxylate. It is proposed that phosphoenolpyruvate carboxykinase together with pyruvate carboxylase and pyruvate kinase forms a phosphoenolpyruvate shuttle through which energy produced by the Krebs cycle in mitochondria may be exported to cytosol.