label: a 5'-end (5'-triphosphoguanosine)-adenylyl-adenylyl-cytidylyl-adenosine in mRNA + S-adenosyl-L-methionine <=> a 5'-end (5'-triphosphoguanosine)-(2'-O-methyladenylyl)-adenylyl-cytidylyl-adenosine in mRNA + S-adenosyl-L-homocysteine + H(+)
label_lc: a 5'-end (5'-triphosphoguanosine)-adenylyl-adenylyl-cytidylyl-adenosine in mrna + s-adenosyl-l-methionine <=> a 5'-end (5'-triphosphoguanosine)-(2'-o-methyladenylyl)-adenylyl-cytidylyl-adenosine in mrna + s-adenosyl-l-homocysteine + h(+)