Enzyme Activity Measurement of NAD(P)H dehydrogenase (quinone) Using Spectrophotometric Assays

Creative Enzymes stands out in the enzyme service industry with innovation and profession. Our high-quality services and professional processes have been praised by tens of thousands of customers. The highly accurate and reproducible results are assured by our advanced equipment and specialized experts. Enzyme activity assays of oxidoreductase, such as NAD(P)H dehydrogenase (quinone), are among our most welcomed services.

NAD(P)H dehydrogenase (quinone) (EC 1.6.5.2, NQO1, formerly EC 1.6.99.2) is a ubiquitous flavoenzyme that catalyzes two-electron reduction of various quinones with the ability to use the cofactors NADH and NADPH with equal efficiency. The catalytic cycle of this enzyme functions via a “ping-pong” mechanism, with the first step of hydride transfer from NAD(P)H to the FAD cofactor, followed by a release of NAD(P)⁺ and hydride transfer from the reduced cofactor to the substrate.

NAD(P)H dehydrogenase (quinone) has a broad spectrum of substrate structures with the preference of short-chain acceptor quinones, such as ubiquinone, benzoquinone, juglone, and duroquinone. NQO1 is generally considered to be a detoxification enzyme, playing an antioxidant role by preventing the formation of reactive oxygen species. In addition to its role in the detoxification of quinones, other functions of this enzyme include the bioactivation of certain antitumor quinone. The abnormal growth and proliferation in different types of tumor cell lead to an overexpressed level of this enzyme, which promotes more research targeted at its competitive inhibition. More recently, studies have shown that NQO1 plays an important role in regulating the stability of the tumor suppressor protein p53 and several other short-lived proteins including p73α and ornithine decarboxylase (ODC). By competing with NAD(P)H for binding to NQO1, inhibitors can prevent electron transfer to FAD, disrupting the associate of this enzyme to p53 and inducing ubiquitin-independent p53 degradation. Nowadays, the competitive inhibitors with superior pharmacological properties will facilitate a more definitive study of NQO1. Creative Enzymes will support your work by providing precise assay services for both enzyme extractions and intracellular enzymes.

Figure: The crystal structure of NQO1 with the inhibitor dicoumarol.
Reference: Asher G et al. Biochemistry. 2006 23;45(20):6372-6378

Creative Enzymes is a well-recognized expert in enzyme activity measurement. Our professional services are based on years of learning and the thorough expertise development. In the future, Creative Enzymes will make every effort to perfecting enzyme activity assays to support your research.