A dual cofactor-specific isocitrate dehydrogenase fromPythium ultimum
| Autor: | John D. Weete, Zahid Mozaffar, Hakryul Kim |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Hot Temperature
Cations Divalent Microorganism Immunology Pythium Applied Microbiology and Biotechnology Microbiology Cofactor Enzyme Stability Genetics Phycomycetes Molecular Biology chemistry.chemical_classification Regulatory enzymes biology Isocitrate Dehydrogenase (NAD+) Stereoisomerism General Medicine Cations Monovalent Hydrogen-Ion Concentration NAD biology.organism_classification Lipids Isocitrate Dehydrogenase Pythium ultimum Molecular Weight Kinetics Isocitrate dehydrogenase Enzyme Biochemistry chemistry biology.protein NADP |
| Zdroj: | Canadian Journal of Microbiology. 42:1241-1247 |
| ISSN: | 1480-3275 0008-4166 |
| DOI: | 10.1139/m96-160 |
| Popis: | Isocitrate dehydrogenase is considered to be one of the key regulatory enzymes in the conversion of glucose into fatty acids by oleaginous microorganisms. A dual coenzyme-specific isocitrate dehydrogenase (EC 1.1.1.41) (IDH) was isolated from the primitive fungus Pythium ultimum and purified by 211-fold by sequential ion-exchange, affinity, and gel filtration chromatographies. Specific activity of the partially purified enzyme was 76.2 μmol/(min∙mg protein) with NAD+and 40% less active with NADP+. Optimum pH for activity was 8.5–9.5. Kmvalues for threo-D-isocitrate and NAD+were 0.031 and 0.55 mM, respectively. The estimated molecular mass of the IDH was 96 kDa under nondenaturing conditions and 48 kDa under denaturing conditions, suggesting that the enzyme is composed of two subunits of the same size. The enzyme was relatively stable up to 55 °C, but no activity was detected after exposure to 65 °C for 15 min. Mg2+or Mn2+were required for activity.Key words: isocitric dehydrogenase, Pythium ultimum, dual cofactor specific, oleaginicity. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|