a 5'-end (N(7)-methyl 5'-triphosphoguanosine)-(2'-O-methyl-guanosine) in mRNA + S-adenosyl-L-homocysteine + H(+) => a 5'-end (N(7)-methyl 5'-triphosphoguanosine)-guanosine in mRNA + S-adenosyl-L-methionine
a 5'-end (n(7)-methyl 5'-triphosphoguanosine)-(2'-o-methyl-guanosine) in mrna + s-adenosyl-l-homocysteine + h(+) => a 5'-end (n(7)-methyl 5'-triphosphoguanosine)-guanosine in mrna + s-adenosyl-l-methionine