Enzyme Activity Measurement for Purine-Nucleoside Phosphorylase Using Spectrophotometric Assays

Creative Enzymes is a leading company of high-quality bioanalytical services. We provide contract personalized research specialized in enzyme activity analysis serving the needs of our clients from all over the world. Fully equipped with the most advanced spectrophotometric instruments, all assays are performed in a professional and timely manner. Herein, we are proud to offer the reliable activity assay for purine-nucleoside phosphorylase.

Purine-nucleoside phosphorylase (EC 2.4.2.1; PNPase) is an enzyme that catalyzes the reversible conversion of purine nucleosides (inosine and guanosine) and deoxynucleosides (deoxyinosine and deoxyguanosine) to their respective purine bases and to pentose 1-phosphate. Purine-nucleoside phosphorylase is a ubiquitous enzyme, which is instrumental in the salvage metabolic pathway and necessary for proper synthesis and degradation of DNA in a living cell.

Purine-nucleoside phosphorylases can be further sorted into two classes, trimeric and hexameric. Trimeric purine-nucleoside phosphorylases, also known as mammalian purine nucleoside phosphorylase, are specific for 6-oxopurine nucleosides and are found both in higher organisms and in procaryotes. Hexameric purine-nucleoside phosphorylases are found only in lower organisms and have broader substrate specificity, accepting both 6-amino and 6-oxopurine nucleosides. Although the active site residues of trimeric and hexameric purine-nucleoside phosphorylases show considerable differences, the mechanisms are thought to be similar. The differences in substrate specificity between the hexameric and trimeric purine-nucleoside phosphorylases suggest a strategy for anticancer suicide gene therapy. Thus, purine-nucleoside phosphorylases are attracting an ever-increasing interest for being used in cancer therapy. In addition, the lack of activity of trimeric purine-nucleoside phosphorylase in humans leads to selective immunodeficiency, as a result of the incorrect T-cell proliferation. Therefore development of new selective immunosuppressive drugs and anticancer agents would benefit from discovery of the enzyme inhibitors.

To investigate the functional significance of purine-nucleoside phosphorylases, it is considerably important to be able to monitor the activity of purine-nucleoside phosphorylases. To serve the purpose, Creative Enzymes made the accurate activity assay available for purine-nucleoside phosphorylases, based on extensive experiences on exploring the enzymes and optimizing the method. The activity of this enzyme is determined at 293nm by measuring the liberation of uric acid spectrophotometrically.

With years of discovery and development, Creative Enzymes has emerged as a worldwide leader in the services of enzyme activity measurement. Regardless of the challenges which may lie on your way to enzyme applications, Creative Enzymes will always meet the requirements for the next stage and will be your best choice of service provider.

Figure： The crystal structure of the E. coli purine-nucleoside phosphorylase hexamer.
Reference: Bennett E M, et al. Journal of Biological Chemistry, 2003, 278(47): 47110-47118.