label: cytidine(72) in tRNA + S-adenosyl-L-methionine => 5-methylcytidine(72) in tRNA + S-adenosyl-L-homocysteine + H(+)
label_lc: cytidine(72) in trna + s-adenosyl-l-methionine => 5-methylcytidine(72) in trna + s-adenosyl-l-homocysteine + h(+)