Bisphosphate 3'-nucleotidase 1 (BPNT1)

Bisphosphate 3'-nucleotidase 1 (BPNT1) is a magnesium-dependent enzyme that plays a pivotal role in the metabolism of nucleotides and sulfur [1][2]. It specifically catalyzes the conversion of 3'-phosphoadenosine-5'-phosphate (PAP) to adenosine 5'-monophosphate (AMP) and inorganic phosphate [1][3]. This activity is essential because PAP is a potent competitive inhibitor of sulfotransferases, the enzymes responsible for the sulfation of various endogenous and exogenous compounds [3][4]. By regulating PAP levels, BPNT1 ensures the continued efficiency of cellular sulfation pathways, which are vital for hormone regulation, detoxification, and structural integrity of the extracellular matrix [4][5]. The enzyme is of significant pharmacological interest because it is a primary target of lithium, a common treatment for bipolar disorder [2][6]. Lithium acts as an uncompetitive inhibitor of BPNT1, leading to an accumulation of PAP and a subsequent decrease in sulfotransferase activity, which may contribute to both its therapeutic effects and its side-effect profile [1][3]. Additionally, BPNT1 is highly sensitive to inhibition by lead, suggesting a role in the pathophysiology of lead poisoning [7]. Understanding BPNT1's function and its inhibition by metal ions provides insights into metabolic regulation and the development of targeted therapies for mood disorders and toxicological conditions [2][5].

Other names

3'(2'),5'-bisphosphate nucleotidase 1PAP-inositol-1,4-bisphosphate phosphatasePhosphoadenosine phosphate phosphataseBPNT1BPNT

Lithium and lead act as inhibitors of BPNT1; lithium specifically acts as an uncompetitive inhibitor, causing the accumulation of 3'-phosphoadenosine-5'-phosphate (PAP), which inhibits sulfotransferases [1][3].