methyltransferase cap1 activity
methyltransferase cap1 activity
Catalysis of the reaction: a 5'-end (N(7)-methyl 5'-triphosphoguanosine)-ribonucleoside in mRNA or snRNA + S-adenosyl-L-methionine = a 5'-end (N(7)-methyl 5'-triphosphoguanosine)-(2'-O-methyl-ribonucleoside) in mRNA or snRNA + S-adenosyl-L-homocysteine + H+. This activity catalyzes the methylation of the ribose on the first transcribed nucleotide of mRNAs and snRNAs.