label: cytidine(48) in tRNA precursor + S-adenosyl-L-methionine => 5-methylcytidine(48) in tRNA precursor + S-adenosyl-L-homocysteine + H(+)
label_lc: cytidine(48) in trna precursor + s-adenosyl-l-methionine => 5-methylcytidine(48) in trna precursor + s-adenosyl-l-homocysteine + h(+)