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