In proline degradation, the enzyme proline dehydrogenase produces P5C from proline, and the enzyme 1-pyrroline-5-carboxylate dehydrogenase converts GSA to glutamate.
During proline metabolism, the enzyme proline dehydrogenase converts proline into P5C, while another enzyme, 1-pyrroline-5-carboxylate dehydrogenase, changes GSA into glutamate.