Acyl-protein synthetase activates tetradecanoic acid. It is a component of the fatty acid reductase complex responsible for converting tetradecanoic acid to the aldehyde which serves as substrate in the luciferase-catalyzed reaction. a long-chain fatty acid + ATP + L-cysteinyl-[protein] = AMP + diphosphate + S-(long-chain fatty acyl)-L-cysteinyl-[protein] Lipid metabolism; fatty acid reduction for biolumincescence. Belongs to the LuxE family.