Bisphosphate 3'-nucleotidase 1 (BPNT1) (BPNT1)

Bisphosphate 3'-nucleotidase 1 (BPNT1) is a magnesium-dependent enzyme that plays a pivotal role in the sulfur activation pathway by hydrolyzing 3'-phosphoadenosine 5'-phosphate (PAP) into adenosine 5'-monophosphate (AMP) and inorganic phosphate [1]. By maintaining low intracellular levels of PAP, BPNT1 prevents the inhibition of sulfotransferases, which are essential for the sulfation of various biological molecules including proteins and hormones [3]. BPNT1 is a primary pharmacological target of lithium, a common treatment for bipolar disorder; lithium acts as an uncompetitive inhibitor of the enzyme at therapeutic concentrations [2]. This inhibition leads to a significant accumulation of PAP, which is hypothesized to contribute to both the mood-stabilizing effects and the side-effect profile of lithium therapy [4]. Beyond its role in metabolism, BPNT1 activity is linked to RNA processing and cellular stress responses, making it a critical factor in cellular homeostasis [1]. Consequently, BPNT1 is a subject of intense study for understanding lithium's mechanism of action and for the development of novel therapeutic agents with improved safety profiles.

Other names

3'(2'),5'-bisphosphate nucleotidase 1PAP phosphatasePhosphoadenosine phosphate phosphatasePAP-inositol-1,4-phosphataseBPNT1

Lithium acts as an uncompetitive inhibitor of BPNT1, leading to the accumulation of 3'-phosphoadenosine 5'-phosphate (PAP), which subsequently inhibits sulfotransferases and other PAP-sensitive enzymes [2, 3].