Part of the bacABCDEFG operon responsible for the biosynthesis of bacilysin, an irreversible inactivator of the glutaminase domain of glucosamine synthetase. Catalyzes the dehydrogenation of the C7-hydroxyl group in the 4S-tetrahydrotyrosine (4S-H4Tyr) to yield anticapsin (epoxycyclohexanonyl-Ala). L-dihydroanticapsin + NAD(+) = H(+) + L-anticapsin + NADH Antibiotic biosynthesis; bacilysin biosynthesis. Belongs to the short-chain dehydrogenases/reductases (SDR) family.