Vanadium inhibition of yeast glucose-6-phosphate dehydrogenase
| Autor: | Wei Cheng-I, Asok C. Sen, Mitchell D. Cohen |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
biology
Inorganic chemistry Vanadium chemistry.chemical_element Dehydrogenase Phosphate Cofactor Vanadium oxide Inorganic Chemistry chemistry.chemical_compound Ammonium metavanadate chemistry Materials Chemistry biology.protein Glucose-6-phosphate dehydrogenase Vanadate Physical and Theoretical Chemistry Nuclear chemistry |
| Zdroj: | Inorganica Chimica Acta. 138:179-186 |
| ISSN: | 0020-1693 |
| DOI: | 10.1016/s0020-1693(00)81220-7 |
| Popis: | Vanadium in the +5 and +4 oxidation states inhibits the activity of yeast glucose-6-phosphate dehydrogenase in a Tris buffer system. The results presented here are the first to report the inhibitory effects of vanadium oxide(IV) on this enzyme. The inhibition by ammonium metavanadate(V) is mixed- type against glucose-6-phosphate, and competitive against NADP+ with Ki values of 2.1 and 2.7 mM, respectively. Theorell-Yonetani analysis indicates that vanadate and phosphate are mutually exclusive inhibitors. Inhibition by vanadium oxide is mixed- type for both substrates. Ki values of 49 and 52 μM for the sugar phosphate and NADP+, respectively, are almost two orders of magnitude lower than those from phosphate or sulfate, and fifty-fold lower than that obtained with vanadate. Vanadium complexation with, and oxidation of, the reduced cofactor is apparent. Analysis of fluorescence quenching by vanadate and vanadium oxide indicates association constants of 4.0 × 102 and 4.3 × 103 M−1, respectively. NMR analysis indicates that interactions of NADPH with vanadium occur primarily through the adenine moiety. |
| Databáze: | OpenAIRE |
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