Search
mRNA guanylyltransferase activity (GO:0004484)
Catalysis of the reaction: GTP + (5')pp-Pur-mRNA = diphosphate + G(5')ppp-Pur-mRNA; G(5')ppp-Pur-mRNA is mRNA containing a guanosine residue linked 5' through three phosphates to the 5' position of the terminal residue.
General
RNA guanylyltransferase activity (GO:0008192)
References
gene ontology: GO:0004484