Purine Nucleoside Phosphorylase Activity Assay Kit (Fluorometric)

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

Nucleoside phosphorylase also known as PNP or purine nucleoside phosphorylase is an enzyme with a vital mechanical role in nucleoside metabolism. The enzyme facilitates the phosphorolytic cleavage of the glycosidic bond in nucleosides producing ribose 1-phosphate and free bases such as guanine and hypoxanthine. This catalytic function plays an important part in nucleotide salvage pathways. PNP has a molecular mass of approximately 32000 Daltons and shows expression predominantly in the lymphoid tissues including the thymus and spleen.

Biological function summary

Nucleoside phosphorylase is important in maintaining nucleotide homeostasis. It operates as a monomer or part of a homotrimeric complex which allows it to efficiently catalyze its reactions in purine metabolism. The absence or dysfunction of PNP results in the accumulation of nucleosides and diminished levels of nucleotide pools which can severely hamper DNA replication and repair.

Pathways

Nucleoside phosphorylase plays an integral role in the purine salvage pathway which is vital for recycling purines to form new nucleotides. It works alongside other enzymes such as adenine phosphoribosyltransferase to conserve energy by recycling purines. This pathway connects closely with the hypoxanthine-guanine phosphoribosyltransferase (HGPRT) pathway showing how PNP is intertwined in broader nucleotide biosynthesis and degradation processes.

Associated diseases and disorders

Deficiencies in nucleoside phosphorylase correlate strongly with immunodeficiencies notably purine nucleoside phosphorylase deficiency (PNP deficiency) which leads to compromised T-cell immunity. This condition can result in recurrent infections and developmental delay. Additionally the enzyme's dysregulation associates with certain leukemias where altered nucleotide pools contribute to the proliferation of malignant cells. In these contexts PNP interacts with proteins central to these disorders including those involved in purine metabolism placing it at a critical junction for potential therapeutic intervention.