GMP reductase 1

GMP reductase 1 (GMPR) is a 345-amino-acid cytoplasmic enzyme that catalyzes the NADPH-dependent deamination of GMP to IMP (UniProt: P36959). This reaction is critical for converting guanine nucleotide derivatives to adenine nucleotides and maintaining the intracellular balance between A and G nucleotides, which is essential for nucleotide metabolism and purine homeostasis.

GMPR is broadly expressed in human tissues and participates in nucleotide salvage and catabolism pathways. No specific disease associations are documented in UniProt for this protein.

In Alzheimer's disease, GMPR shows a consistent upregulation in post-mortem brain tissue. Quantitative proteomics analysis of AD brain versus age-matched controls identified GMPR as significantly elevated with a mean log2 fold-change of 1.509 across 2 of 4 subcellular fractions (P2, P3, S2, S3 by TMT-labeled DDA; Chaparral AD proteomics). This upregulation may reflect altered nucleotide metabolism or cellular stress responses in AD pathology.