Scheme 1. Reactions catalysed by the bifunctional PutA enzyme. The PRODH domain catalyses the oxidation of proline to P5C using a flavin cofactor as the electron acceptor. P5C undergoes a non-enzymatic hydrolysis, resulting in GSA. The P5C dehydrogenase domain (P5CDH) catalyses the NAD+-dependent oxidation of GSA to glutamate thereby generating NADH.
