label: 5-methylcytidine(2499) in 23S rRNA + S-adenosyl-L-homocysteine + H(+) => cytidine(2499) in 23S rRNA + S-adenosyl-L-methionine
label_lc: 5-methylcytidine(2499) in 23s rrna + s-adenosyl-l-homocysteine + h(+) => cytidine(2499) in 23s rrna + s-adenosyl-l-methionine