Description
This enzyme catalyses the methylation of the ribose on the first transcribed nucleotide of mRNA or snRNA molecules, which may be either guanosine or adenosine. This methylation event is known as cap1, and occurrs in all mRNAs and snRNAs of higher eukaryotes, including insects, vertebrates and their viruses. The human enzyme can also methylate mRNA molecules that lack methylation on the capping 5'-triphosphoguanosine