a ribonucleotidyl-ribonucleotide-RNA + GMP + diphosphate => a 3'-end 3'-phospho-ribonucleotide-RNA + a 5'-end dephospho-ribonucleoside-RNA + GTP
a ribonucleotidyl-ribonucleotide-rna + gmp + diphosphate => a 3'-end 3'-phospho-ribonucleotide-rna + a 5'-end dephospho-ribonucleoside-rna + gtp