| Autor: |
J M, Chirgwin, T F, Parsons, E A, Noltmann |
| Rok vydání: |
1975 |
| Předmět: |
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| Zdroj: |
The Journal of biological chemistry. 250(18) |
| ISSN: |
0021-9258 |
| Popis: |
In contrast to the strongly pH-dependent inhibition of phosphoglucose isomerase by substrate analogues with a free carboxyl group, inhibition of this enzyme by neutral sugar phosphates is essentially invariant between pH 7 and 9. Competitive inhibition constants for glucitol 6-phosphate (40 muM), arabinose 5-phosphate (50 muM), and erythritol 4-phosphate (100 muM) were found to be of the same order of magnitude as that reported previously for substrate binding constants (50 to 240 muM). The unique exception is erythrose 4-phosphate whose Ki (0.7 muM, independent of pH) reflects a tightness of binding similar to that found at pH values near or below neutrality for the transition state analogue 5-phosphorarabinonate. The pH independence of inhibition by erythrose 4-phosphate and other neutral sugar phosphates may reflect a mode and locus of binding to phosphoglucose isomerase different from that of the aldonate inhibitors. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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