3'(2'),5'-bisphosphate nucleotidase 1

BPNT1 (3'(2'),5'-bisphosphate nucleotidase 1) is a phosphatase enzyme that hydrolyzes toxic phosphorylated metabolites, including 3'(2')-phosphoadenosine 5'-phosphate (PAP) and inositol bisphosphates, converting them to less-active forms (UniProt: O95861). This catalytic activity prevents the accumulation of PAP, which inhibits sulfotransferases and RNA processing enzymes, and likely contributes to inositol recycling and phosphoinositide metabolism. The enzyme shows substrate selectivity, remaining inactive on 3'-AMP, inositol-1-phosphate, and inositol-1,4,5-triphosphate.

BPNT1 is expressed broadly in human tissues with roles in nucleotide and phosphoinositide homeostasis. No primary diseases are annotated in the UniProt record (UniProt: O95861), but the protein has been identified as relevant to Alzheimer's Disease pathology.

In Alzheimer's Disease brain tissue, BPNT1 is upregulated relative to age-matched controls, with a mean log2 fold-change of +0.20 (Chaparral AD proteomics). This elevation was detected in human post-mortem AD brain across subcellular fractions using quantitative proteomics. The functional significance of BPNT1 upregulation in AD neuropathology requires further investigation.