Guanosine Monophosphate Reductase 1 (GMPR1)

Guanosine monophosphate reductase (EC 1.7.1.7) catalyzes the irreversible NADPH-dependent reductive deamination of guanosine monophosphate (GMP) to inosine monophosphate (IMP). GMPR is able to convert guanosine nucleotides to the pivotal precursor of both guanine (G) and adenine (A) nucleotides.

GMPR gene spans about 50 kb and contains 9 exons. The gene contains 2 potential Sp1 binding sites within exon 1, and a functional, atypical polyadenylation signal in exon 9.The frequency of the ile256 variant was thought to be about 30%. A silent C-to-T change at codon 630 was also found, with a frequency of about 10%; the silent change created an additional restriction cleavage site.