Trans-enoyl reductase; part of the gene cluster 23 that mediates the biosynthesis of a family of 2-pyridones known as leporins (PubMed:20447271, PubMed:26051490). The hybrid PKS-NRPS synthetase lepA and the enoyl reductase lepG are responsible for fusion of phenylalanine with a hexaketide and subsequent release of the stable tetramic acid precursor, pre-leporin C (PubMed:26051490). Because lepA lacks a designated enoylreductase (ER) domain, the required activity is provided the enoyl reductase lepG (PubMed:26051490). It is possible that the dehydrogenase lepF also participates in production of pre-leporin C (PubMed:26051490). Cytochrome P450 monooxygenase lepH is then required for the ring expansion step to yield leporin C (PubMed:26051490). Leporin C is then presumably further oxidized by the N-hydroxylase lepD to form leporin B (PubMed:26051490). LepI may possess a function in biosynthesis upstream of lepA (PubMed:26051490). Leporin B is further oxidized in the presence of ferric ion to give the leporin B trimer-iron chelate, but whether or not this reaction is catalyzed by an enzyme in the pathway or by ferric ion is not determined yet (PubMed:26051490). Monomer. Impairs the production od leporins B and C or any other potential open ring 2-pyridone (PubMed:26051490). Belongs to the zinc-containing alcohol dehydrogenase family.