label: cytidine(839) in 12S rRNA + S-adenosyl-L-methionine <=> N(4)-methylcytidine(839) in 12S rRNA + S-adenosyl-L-homocysteine + H(+)
label_lc: cytidine(839) in 12s rrna + s-adenosyl-l-methionine <=> n(4)-methylcytidine(839) in 12s rrna + s-adenosyl-l-homocysteine + h(+)