Catalyzes the reduction of Delta(1)-pyrroline-2-carboxylate (Pyr2C) to L-proline, using preferentially NADPH over NADH as the electron donor. Together with LhpH, is involved in a metabolic pathway that converts trans-3-hydroxy-L-proline (t3LHyp) to L-proline. To a much lesser extent, can also reduce Delta(1)-piperideine-2-carboxylate (Pip2C) to L-pipecolate in vitro; however, this activity has likely no physiological significance in vivo since C.psychrerythraea probably possesses no ability to metabolize D-lysine via the L-pipecolate pathway. Does not show ornithine cyclodeaminase (OCD) activity. L-proline + NAD(+) = 1-pyrroline-2-carboxylate + H(+) + NADH L-proline + NADP(+) = 1-pyrroline-2-carboxylate + H(+) + NADPH kcat is 7470 min(-1) for Pyr2C reduction using NADPH. kcat is 621 min(-1) for Pyr2C reduction using NADH. kcat is 82.0 min(-1) for Pip2C reduction using NADPH. kcat is 5.27 min(-1) for Pip2C reduction using NADH. kcat is 61.3 min(-1) for Delta(1)-pyrroline-(4S)-hydroxy-2-carboxylate (Pyr4SH2C) reduction using NADPH. kcat is 65.3 min(-1) for L-proline oxidation using NADP(+). kcat is 0.415 min(-1) for L-proline oxidation using NAD(+). kcat is 1.28 min(-1) for L-pipecolate oxidation using NADP(+). Optimum pH is 6.5 for Pyr2C reduction and 10.5 for L-proline oxidation. Homodimer. Belongs to the ornithine cyclodeaminase/mu-crystallin family.