| Autor: |
Anil K. Gupta, Arvind Gill, Narinder Kaur |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Phytochemistry. 49:55-58 |
| ISSN: |
0031-9422 |
| DOI: |
10.1016/s0031-9422(97)00854-6 |
| Popis: |
An extracellular inulinase (EC 3.2.1.7) from Aspergillus oryzae growing on inulin-containing medium was purified by CM-cellulose and Sephadex G-200 column chromatographies to electrophoretic homogeneity. The purified inulinase cleaved β -linked fructose from inulin and sucrose with S\I ratio of 2.4. It had a remarkable stability in heat, losing only 41 and 32% of its inulin hydrolytic activity after 2 h at 90° and 100°, respectively. The pattern of thermal denaturation of both the inulin and sucrose hydrolytic activities was nearly the same. SO 2− 4 and Fe 3 were strong inhibitors of inulin and sucrose hydrolytic activities, whereas Ba 2 was an activator. Hg 2 inhibited sucrose hydrolytic activity but increased inulin hydrolytic activity of inulinase. It is proposed that inulinase has different sites for binding of sucrose and inulin and these are either very close to or partially overlapping. The sulphydryl group is in the non-overlapping zone of the sucrose binding site and its modification by HgCl 2 results in an enhanced inulin hydrolytic activity. In the presence of inulin and sucrose together, both substrates compete with each other resulting in reduced activity compared with that observed with individual substrates. Inulinase had a temperature optima of 55° and a mass of 38 kd. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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