During gluconeogenesis reducing equivalents from mitochondria to cytosol are transported by -

↵ Gluconeogenesis is a reversal of the glycolytic pathway except for 4 thermodynamic barriers. These 4 energy barriers are:- Between pyruvate and phosphoenolpyruvate Between fructose 1, 6-bisphosphate and fructose 6-phosphate Between glucose 6-phosphate and glucose Between glucose 1-phosphate and glycogen Reducing equivalents (NADH+H+) are transported from mitochondria to cytosol in overcoming the 1" barrier i.e. ­between pyruvate and phosphoenolpyruvate. Conversion of pyruvate to phosphoenolpyruvate is achieved by 2 enzymes:- Pyruvate carboxylase, a mitochondrial enzyme converts pyruvate to oxaloacetate (OAA). Phosphoenolpyruvate carboxykinase, present chiefly in the cytosol, converts OAA to phosphoenolpyruvate. It is noted here that OAA is formed inside the mitochondria but the reaction to convert it into phosphoenolpyruvate occurs in cytosol and OAA is not permeable to the mitochondrial membrane. The OAA is transferred to the cytosol by 2 mechanisms:- By formation of Malate By formation of Citrate The conversion of OAA to Malate and further of Malate to phosphoenolpyruvate is depicted below. The reducing equivalents (NADH+.1-1+) are transferred across the mitochondrial membrane, along with transport of OAA in the form of malate.