2-oxobutanoate + FADH2 => (2R)-hydroxybutanoate + FAD + H(+)
2-oxobutanoate + fadh2 => (2r)-hydroxybutanoate + fad + h(+)
2-oxobutanoate + FADH2 => (2R)-hydroxybutanoate + FAD + H(+)
2-oxobutanoate + fadh2 => (2r)-hydroxybutanoate + fad + h(+)