Catalytic properties of thermophilic lactate dehydrogenase and halophilic malate dehydrogenase at high temperature and low water activity
| العنوان: | Catalytic properties of thermophilic lactate dehydrogenase and halophilic malate dehydrogenase at high temperature and low water activity |
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| المؤلفون: | Rainer Jaenicke, Katrin Hecht, Alexander Wrba |
| المصدر: | European Journal of Biochemistry. 183:69-74 |
| بيانات النشر: | Wiley, 1989. |
| سنة النشر: | 1989 |
| مصطلحات موضوعية: | Halobacterium, Gram-Negative Anaerobic Bacteria, L-Lactate Dehydrogenase, biology, Water activity, Thermophile, Temperature, Water, Substrate (chemistry), Sodium Chloride, biology.organism_classification, Biochemistry, Malate dehydrogenase, Catalysis, Halophile, Mitochondria, Enzyme Activation, Kinetics, Enzyme activator, chemistry.chemical_compound, chemistry, Malate Dehydrogenase, Thermotoga maritima, Lactate dehydrogenase |
| الوصف: | Thermophilic lactate dehydrogenases from Thermotoga maritima and Bacillus stearothermophilus are stable up to temperature limits close to the optimum growth temperature of their parent organisms. Their catalytic properties are anomalous in that Km shows a drastic increase with increasing temperature. At low temperatures, the effect levels off. Extreme halophilic malate dehydrogenase from Halobacterium marismortui exhibits a similar anomaly. Increasing salt concentration (NaCl) leads to an optimum curve for Km, oxaloacctate while Km, NADH remains constant. Previous claims that the activity of halophilic malate dehydrogenase shows a maximum at 1.25 M NaCl are caused by limiting substrate concentration; at substrate saturation, specific activity of halophilic malate dehydrogenase reaches a constant value at ionic strengths I greater than or equal to 1 M. Non-halophilic (mitochondrial) malate dehydrogenase shows Km characteristics similar to those observed for the halophilic enzyme. The drastic decrease in specific activity of the mitochondrial enzyme at elevated salt concentrations is caused by the salt-induced increase in rigidity of the enzyme, rather than gross structural changes. |
| تدمد: | 1432-1033 0014-2956 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::40608e2dcd81abd86552a578835edecbTest https://doi.org/10.1111/j.1432-1033.1989.tb14897.xTest |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....40608e2dcd81abd86552a578835edecb |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14321033 00142956 |
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