label: N(alpha)-methyl-L-tryptophan + S-adenosyl-L-homocysteine + H(+) => L-tryptophan + S-adenosyl-L-methionine
label_lc: n(alpha)-methyl-l-tryptophan + s-adenosyl-l-homocysteine + h(+) => l-tryptophan + s-adenosyl-l-methionine