butanoyl-CoA + FAD + H(+) => (2E)-butenoyl-CoA + FADH2
butanoyl-coa + fad + h(+) => (2e)-butenoyl-coa + fadh2
butanoyl-CoA + FAD + H(+) => (2E)-butenoyl-CoA + FADH2
butanoyl-coa + fad + h(+) => (2e)-butenoyl-coa + fadh2