5-methylcytidine(50) in tRNA + S-adenosyl-L-homocysteine + H(+) => cytidine(50) in tRNA + S-adenosyl-L-methionine
5-methylcytidine(50) in trna + s-adenosyl-l-homocysteine + h(+) => cytidine(50) in trna + s-adenosyl-l-methionine