BPNT1

BPNT1 is a human enzyme encoded by the BPNT1 gene and is also referred to as 3’-phosphoadenosine-5’-phosphate phosphatase or bisphosphate 3’-nucleotidase 1. It is a magnesium-dependent hydrolase that catalyzes the reaction 3’-phosphoadenosine-5’-phosphate (PAP) plus water to adenosine monophosphate (AMP) and phosphate. By hydrolyzing PAP, BPNT1 helps regulate the cellular balance of PAP and its related sulfation substrate PAPS (3’-phosphoadenosine-5’-phosphosulfate).

Function and role in sulfation pathways: PAP is a byproduct of sulfotransferase reactions that use PAPS as the sulfate donor. PAP can inhibit sulfotransferases if it accumulates. BPNT1 removes PAP, thereby enabling continued sulfation of a broad range of substrates, including glycosaminoglycans, proteoglycans, and glycoproteins. This sulfation is essential for the structure and function of the extracellular matrix, cell signaling, and protein stability.

Localization and enzymatic family: BPNT1 is associated with the Golgi apparatus in mammalian cells, where many sulfation reactions take place, and it belongs to the haloacid dehalogenase (HAD) superfamily of phosphatases. The enzyme requires divalent metal ions for its catalytic activity and is conserved across vertebrates.

Clinical and genetic notes: BPNT1 is ubiquitously expressed and essential for proper sulfation processes. In model organisms, reduced BPNT1 function disrupts sulfation and can lead to developmental and extracellular matrix defects, highlighting its role in glycan sulfation and related biological processes. Research continues to clarify its contribution to human sulfation-related disorders.