Anti-GMPR antibodies are used in the immunodetection of the protein guanosine monophosphate reductase. In humans, the canonical protein has a reported length of 345 amino acid residues and a mass of 37.4 kDa. A member of a the IMPDH/GMPR protein family, GMPR is known to catalyze the irreversible NADPH-dependent deamination of GMP to IMP. Synonyms for this target antigen include GMPR1, GMP reductase 1, guanine monophosphate reductase, guanosine 5'-monophosphate oxidoreductase 1, guanosine monophosphate reductase 1, and GMPR 1.