label: N(alpha),N(alpha)-dimethyl-L-histidine + S-adenosyl-L-methionine => hercynine + S-adenosyl-L-homocysteine + H(+)
label_lc: n(alpha),n(alpha)-dimethyl-l-histidine + s-adenosyl-l-methionine => hercynine + s-adenosyl-l-homocysteine + h(+)