s3. Pyruvate is converted to phosphoenolpyruvate(PEP)via two alternative paths In both paths, pyr uvate is converted to oxaloacetate with the catalysis of pyruvate carboxylase)in mitochondria In one path, oxaloacetate is converted directly to PEP in the matrix of mitochondria in a reaction catalyzed by the mitochondrial PEP carboxykinase isozyme, PEP is then transported to the cytosol for further conversion3. Pyruvate is converted to phosphoenoylpyruvate (PEP) via two alternative paths • In both paths, pyruvate is converted to oxaloacetate (with the catalysis of pyruvate carboxylase) in mitochondria. • In one path, oxaloacetate is converted directly to PEP in the matrix of mitochondria in a reaction catalyzed by the mitochondrial PEP carboxykinase isozyme, PEP is then transported to the cytosol for further conversion