Catalyzes the reduction of both Delta(1)-pyrroline-2-carboxylate (Pyr2C) and Delta(1)-piperideine-2-carboxylate (Pip2C) to L-proline and L-pipecolate, respectively, using NADPH as the electron donor. Cannot use NADH instead of NADPH. Is likely involved in a degradation pathway that converts trans-3-hydroxy-L-proline (t3LHyp) to L-proline, which would allow P.aeruginosa to grow on t3LHyp as a sole carbon source. Can also catalyze the reverse oxidation reactions, albeit at a much lower rate. Is also able to use Delta(1)-pyrroline-(4S)-hydroxy-2-carboxylate (Pyr4SH2C) and cis-4-hydroxy-L-proline (c4LHyp) as substrates, and might be involved in the metabolism of c4LHyp, a compound which is generated by the hydroxylation of free L-proline in bacteria. L-pipecolate + NADP(+) = Delta(1)-piperideine-2-carboxylate + H(+) + NADPH L-proline + NADP(+) = 1-pyrroline-2-carboxylate + H(+) + NADPH cis-4-hydroxy-L-proline + NADP(+) = Delta(1)-pyrroline-(4S)-hydroxy-2-carboxylate + 2 H(+) + NADPH kcat is 2500 min(-1) for Pyr2C reduction. kcat is 2120 min(-1) for Pip2C reduction. kcat is 868 min(-1) for Pyr4SH2C reduction. kcat is 205 min(-1) for L-proline oxidation. kcat is 135 min(-1) for L-pipecolate oxidation. kcat is 272 min(-1) for t3LHyp oxidation. Optimum pH is 7.0 for Pyr2C reduction and 10.0 for L-proline oxidation. Homodimer. Belongs to the LDH2/MDH2 oxidoreductase family.