label: an N(3)-methylcytidine in tRNA + S-adenosyl-L-homocysteine + H(+) => a cytidine in tRNA + S-adenosyl-L-methionine
label_lc: an n(3)-methylcytidine in trna + s-adenosyl-l-homocysteine + h(+) => a cytidine in trna + s-adenosyl-l-methionine