label: cytidine(1920) in 23S rRNA + S-adenosyl-L-methionine <=> 2'-O-methylcytidine(1920) in 23S rRNA + S-adenosyl-L-homocysteine + H(+)
label_lc: cytidine(1920) in 23s rrna + s-adenosyl-l-methionine <=> 2'-o-methylcytidine(1920) in 23s rrna + s-adenosyl-l-homocysteine + h(+)