Conversion of oxaloacetate to phosphoenolpyruvate
Conversion of oxaloacetate to phosphoenolpyruvate: In this reaction, oxaloacetate and guanosine triphosphate (GTP) are converted to PEP, CO, and guanosine diphosphate (GDP). This reaction is catalyzed byphosphoenolpyruvate carboxykinase (PEPCK) which requires Mn++ for its activation. In humans, this enzyme is equally distributed between mitochondria and the cytosol.