Auxiliary enzyme of beta-oxidation. Participates in the degradation of unsaturated fatty enoyl-CoA esters having double bonds in both even- and odd-numbered positions in peroxisome. Catalyzes the NADP-dependent reduction of 2,4-dienoyl-CoA to yield trans-3-enoyl-CoA. Dispensable for growth and sporulation on solid acetate and oleate media, but is essential for these processes to occur on petroselineate. a (2E,4Z)-dienoyl-CoA + H(+) + NADPH = a 4,5-saturated-(3E)-enoyl-CoA + NADP(+) a (2E,4E)-dienoyl-CoA + H(+) + NADPH = a 4,5-saturated-(3E)-enoyl-CoA + NADP(+) Homodimer. Sequentially activated during the process of meiosis and spore formation. By oleate. Transcription is regulated by the transcription factors PIP2, OAF1 and ADR1. Weakly induced during sporulation in diploid cells. Belongs to the short-chain dehydrogenases/reductases (SDR) family.