label: a cytidine in 26S rRNA + S-adenosyl-L-methionine => a 5-methylcytidine in 26S rRNA + S-adenosyl-L-homocysteine + H(+)
label_lc: a cytidine in 26s rrna + s-adenosyl-l-methionine => a 5-methylcytidine in 26s rrna + s-adenosyl-l-homocysteine + h(+)