EC 1.2.1.50; recommended name: long-chain-fatty-acyl-CoA reductase; systematic name: long-chain-aldehyde: NADP+ oxidoreductase (acyl-CoA-forming). An enzyme that catalyses a reaction between a long-chain aldehyde, CoA, and NADP+ to form long-chain acyl-CoA and NADPH. It is part of the bacterial luciferase system. Example: see Lux proteins.