| Autor: |
Eaton RH; University Department of Clinical Chemistry, The Royal Infirmary, Edinburgh 3., Moss DW |
| Jazyk: |
angličtina |
| Zdroj: |
The Biochemical journal [Biochem J] 1967 Mar; Vol. 102 (3), pp. 917-21. |
| DOI: |
10.1042/bj1020917 |
| Abstrakt: |
1. Inhibition of the pyrophosphatase and orthophosphatase activities of human liver and small-intestinal alkaline-phosphatase preparations by different classes of inhibitors has been studied. 2. Each type of substrate, pyrophosphate or orthophosphate, is a competitive inhibitor of hydrolysis of the other type. 3. l-Phenylalanine is a non-competitive inhibitor of both types of activity of the intestinal preparation, but inhibits neither activity of the liver enzyme. Arsenate is a competitive inhibitor of both activities of both preparations. For a given inhibitor, the values of K(i) are independent of the type of substrate used when measurements are made at the same pH. 4. Mg(2+) ions activate orthophosphatase but inhibit pyrophosphatase, except in very low concentrations. 5. These results are compatible with the presence in each tissue preparation of a single enzyme with one type of active centre, possessing both orthophosphatase and pyrophosphatase activities. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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