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. Can catalyze the reverse oxidation reactions, albeit at a much lower rate. Is also able to catalyze in vitro the NADPH-dependent formation of N-methylalanine from pyruvate and N-methylamine; can act on other alpha-keto acids and specifically uses methylamine and not ammonia for these reductive amination reactions. Can use NADH instead of NADPH, although with much less efficiency. L-pipecolate + NADP(+) = Delta(1)-piperideine-2-carboxylate + H(+) + NADPH L-proline + NADP(+) = 1-pyrroline-2-carboxylate + H(+) + NADPH H2O + N-methyl-L-alanine + NADP(+) = H(+) + methylamine + NADPH + pyruvate Is inhibited by the substrate analog pyrrole-2-carboxylate, and by 2-picolinate. Optimum temperature is 30-45 degrees Celsius. Is stable between 0 and 35 degrees Celsius after incubation of 30 minutes. Homodimer. Belongs to the LDH2/MDH2 oxidoreductase family.