Regulation of pyruvate kinases from Fusarium oxysporum
| Autor: | M. W. Zink |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Pyruvate decarboxylation
Pyruvate dehydrogenase kinase Pyruvate Kinase Immunology Biology Applied Microbiology and Biotechnology Microbiology Phosphoenolpyruvic acid Ammonium Chloride chemistry.chemical_compound Adenosine Triphosphate Fusarium Fructosediphosphates Genetics Citrates Molecular Biology Kinase Acetyl-CoA General Medicine Hydrogen-Ion Concentration Pyruvate dehydrogenase complex Molecular Weight Kinetics chemistry Biochemistry Enzyme Induction Potassium Saturation vapor curve Phosphoenolpyruvate carboxykinase |
| Zdroj: | Canadian Journal of Microbiology. 23:1346-1359 |
| ISSN: | 1480-3275 0008-4166 |
| DOI: | 10.1139/m77-204 |
| Popis: | ZINK, M. W. 1977. Regulation of pyruvate kinases from Frrstrrirrtn osysporIrn1. Can. J. Microbiol. 23: 1346-1359. Two types of pyruvate kinases were found in Firsciriirm oxysporlrtn. One type (inducible) was present mainly during the early stages of growth on glucose or sucrose and displayed Michaelis-Menten kinetics with respect to phosphoenolpyruvate and adenosine diphosphate. The major type (constitutive) was present under all conditions of growth and displayed in the absence of potassium ions, a sigmoidal substrate saturation curve when phosphoenolpyruvate was used as the variable substrate. In the presence of potassium ions the saturation curve for phosphoenolpyr~~ vate exhibits a plateau at half-maximal velocity. The effects of various metabolites on the activity of the inducibleand constitutive kinases were alsostudied. Fructose-I, 6-diphosphate, cyclic AMP, acetyl CoA, tryptophan, and phenylalanine had no effect on the activity of the enzymes. Citrate was a potent inhibitor of the constitutive pyruvate kinase activity and increased the sigmoidicity of the saturation curve for phosphoenolpyruvic acid. In the presence of K+, the bimodal plot observed in the absence ofcitrate gradually changed to a hyperbolic shape as the concentration of citric acid was increased. In the presence of K+ and ADP a s the variable substrate citric acid converted the hyperbolic plot to a sigmoidal one. Citrate had no effect on the inducible enzyme. |
| Databáze: | OpenAIRE |
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