PNP
PNP (purine nucleoside phosphorylase, also known as PUNP or NP) is a cytosolic enzyme that breaks down purine nucleosides into free purine bases and pentose-1-phosphate. Loss of PNP function causes a defect in T-cell immunity, which makes it a key protein in immunodeficiency research. Browse Assay Genie's current range of PNP research reagents below, or read on for the biology behind the target.
PNP catalyses the phosphorolytic breakdown of the N-glycosidic bond in beta-(deoxy)ribonucleosides. The reaction yields the corresponding free purine base and pentose-1-phosphate. The enzyme preferentially acts on 6-oxopurine nucleosides, including inosine and guanosine. According to the NCBI Gene summary, the reaction is reversible, so the enzyme catalyses the phosphorolysis of purine nucleosides in both directions.
The PNP gene encodes a protein that belongs to the PNP/MTAP phosphorylase family. The active enzyme is a trimer made up of three identical subunits, and it is found in the cytosol. A known polymorphism at amino acid position 51 does not affect enzyme activity. A pseudogene has also been identified on chromosome 2, which is worth bearing in mind when designing nucleic acid assays for the PNP gene. The mouse and rat orthologues are both named Pnp.
PNP is best known for its link to immune function. Mutations that cause nucleoside phosphorylase deficiency result in defective T-cell (cell-mediated) immunity. They can also affect B-cell immunity and antibody responses. Neurologic disorders may also be apparent in patients with these immune defects. The enzyme was formerly listed under the name nucleoside phosphorylase, and the symbols PUNP and NP are still found in older literature. Researchers studying PNP often work with an anti-PNP antibody, a PNP ELISA kit or recombinant PNP protein to examine expression and activity.
PNP converts inosine, guanosine and related nucleosides into free purine bases and pentose-1-phosphate, making it a central enzyme for studying purine breakdown.
Nucleoside phosphorylase deficiency leads to defective T-cell immunity, so PNP is a reference target in immunodeficiency research.
PNP mutations can also affect B-cell immunity and antibody responses, supporting studies of how purine metabolism shapes immune function.
Neurologic disorders may accompany immune defects in patients with PNP deficiency, which makes the enzyme relevant to work linking metabolism and neurological disease.
PNP catalyses the phosphorolytic breakdown of the N-glycosidic bond in beta-(deoxy)ribonucleosides. This releases a free purine base and pentose-1-phosphate. It preferentially acts on 6-oxopurine nucleosides such as inosine and guanosine, and it works as a trimer of three identical subunits in the cytosol.
The HGNC-approved name is purine nucleoside phosphorylase, and the gene symbol is PNP. Aliases and previous symbols include PUNP and NP. The previous gene name was nucleoside phosphorylase. Searches for any of these terms refer to the same enzyme, EC 2.4.2.1.
Mouse and rat both have an orthologous gene named Pnp. In humans, mutations that cause nucleoside phosphorylase deficiency result in defective T-cell immunity and can also affect B-cell immunity and antibody responses. Check the datasheet of any product for its validated reactivity.
Patatin-like phospholipase domain proteins with similar gene symbols, listed here for navigation only; they are distinct from PNP.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P00491; product specifications from Assay Genie datasheets.