label: a menaquinone + S-adenosyl-L-homocysteine + H(+) => a 2-demethylmenaquinone + S-adenosyl-L-methionine
label_lc: a menaquinone + s-adenosyl-l-homocysteine + h(+) => a 2-demethylmenaquinone + s-adenosyl-l-methionine