2.1.3.1 (S)-methylmalonyl-CoA + pyruvate = propanoyl-CoA + oxaloacetate mechanism 2.1.3.1 (S)-methylmalonyl-CoA + pyruvate = propanoyl-CoA + oxaloacetate partial reaction 1 is catalysed specifically by the 12S subunit, partial reaction 2 is catalysed specifically by the 5S subunit 2.1.3.1 (S)-methylmalonyl-CoA + pyruvate = propanoyl-CoA + oxaloacetate homology model of human pyruvate carboxyltransferase, conserved mechanism