Cadmium(II)-113 NMR studies of the mechanism of metal ion activation of yeast enolase
| Autor: | P.D. Ellis, John M. Brewer, S.G. Spencer |
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| Rok vydání: | 1985 |
| Předmět: |
Reaction mechanism
Binding Sites Magnetic Resonance Spectroscopy Chemistry Protein Conformation Inorganic chemistry Resonance Substrate (chemistry) Saccharomyces cerevisiae Hydrogen-Ion Concentration Biochemistry Catalysis Substrate Specificity Inorganic Chemistry Metal A-site Crystallography Octahedron visual_art Phosphopyruvate Hydratase Octahedral molecular geometry visual_art.visual_art_medium Cadmium |
| Zdroj: | Journal of inorganic biochemistry. 24(1) |
| ISSN: | 0162-0134 |
| Popis: | Yeast enolase binds one mole of 113Cd2+ per subunit at a site that consists of all oxyligands in a distorted octahedral environment. This “conformational” metal ion's environment undergoes further distortion on addition of substrate/product or analogs. At pH's below the optimum value the shifted resonance tends to break up into several, suggesting the existence of several slowly exchanging intermediate forms. At acid pH's, on addition of one additional mole/subunit of 113Cd2+, which greatly increases catalysis, “conformational” resonance(s) further broadens, suggesting that the second, “catalytic” metal ion increases the rates of interconversion between “conformational” species. At more alkaline pH's, near the optimum pH, the “conformational” peak is sharpened, which suggests that very fast interconversion is occurring. The position of the “catalytic” metal ion resonance also suggests all oxyligands in a distorted octahedral geometry. The “catalytic” resonance is often broadened to the point where it cannot be seen, suggesting rapid changes in its geometry due to interconversion of substrate and product. |
| Databáze: | OpenAIRE |
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