Mutants of Escherichia coli deficient in phosphoglucomutase accumulate amylose when the cells are grown on maltose or galactose as carbon source. In the presence of physiological levels of phosphoglucomutase, most of the sugar is catabolized, leading to strongly reduced levels of amylose accumulatio
On enzymatic activity in organic solvents as a function of enzyme history
โ Scribed by Tao Ke; Alexander M. Klibanov
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 63 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0006-3592
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โฆ Synopsis
Catalytic activities of โฃ-chymotrypsin and subtilisin Carlsberg in various hydrous organic solvents were measured as a function of how the enzyme suspension had been prepared. In one method, lyophilized enzyme was directly suspended in the solvent containing 1% water. In another, the enzyme was precipitated from its aqueous solution by a 100-fold dilution with an anhydrous solvent. In most cases, the reaction rate in a given nonaqueous enzymatic system strongly (up to an order of magnitude) depended on the mode of enzyme preparation. The magnitude of this dependence was markedly affected by the nature of the solvent and enzyme. A mechanistic hypothesis proposed to explain the observed dependencies was verified in additional experiments in which the water contents and enzyme history were further varied.
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