| Autor: |
J, Torres-da Matta, A, Nery da Matta, A, Hassón-Voloch |
| Rok vydání: |
1976 |
| Předmět: |
|
| Zdroj: |
Anais da Academia Brasileira de Ciencias. 48(1) |
| ISSN: |
0001-3765 |
| Popis: |
Properties of L(+) lactate dehydrogenase (LDH) of Electrophorus electricus (L.) electric organ were studied, comparing the substrates pyruvate and lactate. Electric organ LDH is a soluble enzyme with a pH optimum of 7.4 for pyruvate and 9.0 for lactate. The apparent Km was lower for pyruvate (Km = 2.5 X 10(-4) M) than for lactate (Km = 1.5 X 10(-2) M). With lactate as a substrate at pH 7.4, malonate, oxalate and pyruvate inhibited competitively. For pyruvate as substrate at pH 9.0 malonate inhibited non-competitively and oxalate shiwed uncompetitive inhibition. The different effects of the carboxylic acids on LDH activity suggest different stereospecificities of the two enzyme-coenzyme complexes in the forward and reserve reactions. The reactions of electric organ LDH with substrates and inhibitors are consistent with electrophoretic analysis suggesting that the enzyme is of the M-type. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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