cytidine(2870) in 25S rRNA + S-adenosyl-L-methionine <=> 5-methylcytidine(2870) in 25S rRNA + S-adenosyl-L-homocysteine + H(+)
cytidine(2870) in 25s rrna + s-adenosyl-l-methionine <=> 5-methylcytidine(2870) in 25s rrna + s-adenosyl-l-homocysteine + h(+)