label: (2R,3R)-2,3-dihydroxy-3-methylpentanoate + NADP(+) <=> (S)-2-ethyl-2-hydroxy-3-oxobutanoate + NADPH + H(+)
label_lc: (2r,3r)-2,3-dihydroxy-3-methylpentanoate + nadp(+) <=> (s)-2-ethyl-2-hydroxy-3-oxobutanoate + nadph + h(+)