label: (3R)-3,4-dimethyl-2-oxopentanoate + S-adenosyl-L-homocysteine + H(+) => 4-methyl-2-oxopentanoate + S-adenosyl-L-methionine
label_lc: (3r)-3,4-dimethyl-2-oxopentanoate + s-adenosyl-l-homocysteine + h(+) => 4-methyl-2-oxopentanoate + s-adenosyl-l-methionine