An NADH/NAD-favored aldo-keto reductase facilitates avilamycin A biosynthesis by primarily catalyzing oxidation of avilamycin C.

Avilamycins, which possess potent inhibitory activity against Gram-positive bacteria, are a group of oligosaccharide antibiotics produced by . Among these structurally related oligosaccharide antibiotics, avilamycin serves as the main bioactive component in veterinary drugs and animal feed additives, which differs from avilamycin only in the redox state of the two-carbon branched-chain of the terminal octose moiety. However, the mechanisms underlying assembly and modification of the oligosaccharide chain to diversify individual avilamycins remain poorly understood.