Converts proline to delta-1-pyrroline-5-carboxylate. a quinone + L-proline = (S)-1-pyrroline-5-carboxylate + a quinol + H(+) Amino-acid degradation; L-proline degradation into L-glutamate; L-glutamate from L-proline: step 1/2. The expression of proline oxidase is controlled by proline and oxygen. Proline oxidase requires a functional electron transport chain aerobiosis for its activity. Present with 184 molecules/cell in log phase SD medium. Belongs to the proline oxidase family.