a 5-methylcytidine in 25S rRNA + S-adenosyl-L-homocysteine + H(+) => a cytidine in 25S rRNA + S-adenosyl-L-methionine
a 5-methylcytidine in 25s rrna + s-adenosyl-l-homocysteine + h(+) => a cytidine in 25s rrna + s-adenosyl-l-methionine