Converts proline to delta-1-pyrroline-5-carboxylate. a quinone + L-proline = (S)-1-pyrroline-5-carboxylate + a quinol + H(+) Optimum pH is 7.5-8. Optimum temperature is 25 degrees Celsius. Loses 70% of activity upon activation at 45 degrees Celsius for 15 minutes. Amino-acid degradation; L-proline degradation into L-glutamate; L-glutamate from L-proline: step 1/2. Belongs to the proline oxidase family.