Oxidizes proline to glutamate for use as a carbon and nitrogen source and also function as a transcriptional repressor of the put operon. a quinone + L-proline = (S)-1-pyrroline-5-carboxylate + a quinol + H(+) H2O + L-glutamate 5-semialdehyde + NAD(+) = 2 H(+) + L-glutamate + NADH Amino-acid degradation; L-proline degradation into L-glutamate; L-glutamate from L-proline: step 1/2. Amino-acid degradation; L-proline degradation into L-glutamate; L-glutamate from L-proline: step 2/2. By proline, autorepression and catabolite repression, and is potentially nitrogen controlled. In the N-terminal section; belongs to the proline dehydrogenase family. In the C-terminal section; belongs to the aldehyde dehydrogenase family.