The phosphoenol-pyruvate branchpoint in adultHymenolepis diminuta (cestoda): A study of pyruvate kinase and phosphoenol-pyruvate carboxykinase
| العنوان: | The phosphoenol-pyruvate branchpoint in adultHymenolepis diminuta (cestoda): A study of pyruvate kinase and phosphoenol-pyruvate carboxykinase |
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| المؤلفون: | R. B. Podesta, W. C. Hulbert, T. Mustafa, D.F. Mettrick, Thomas W. Moon |
| المصدر: | Journal of Experimental Zoology. 200:325-336 |
| بيانات النشر: | Wiley, 1977. |
| سنة النشر: | 1977 |
| مصطلحات موضوعية: | Pyruvate Kinase, education, Buffers, Carbohydrate metabolism, Biology, Phosphoenolpyruvate, Animals, Purine Nucleotides, Alanine, chemistry.chemical_classification, Effector, Osmolar Concentration, General Medicine, Carbon Dioxide, Hydrogen-Ion Concentration, Hymenolepis diminuta, biology.organism_classification, Bicarbonates, Kinetics, Enzyme, chemistry, Biochemistry, Lactates, cardiovascular system, Cestoda, Phosphoenolpyruvate Carboxykinase (GTP), Animal Science and Zoology, Phosphoenolpyruvate carboxykinase, Flux (metabolism), Pyruvate kinase, Hymenolepis, circulatory and respiratory physiology |
| الوصف: | The properties of pyruvate kinase (PK) and phosphoenol pyruvate carboxykinase (PEP CK), two enzymes that determine the preferrential accumulation of either succinate or lactate as endproducts of carbohydrate metabolism, are described in adult Hymenolepis diminuta. PK activity at Vmax and Km levels of PEP was unaffected by ATP, alanine, FDP4, or H+ ions, but was inhibited by 50% at 6.3 mM L-lactate and 30 mM HCO3−. The addition of 30 mM HCO3− increased the Km (PEP) by 6-fold but did not alter the Vmax. The inhibition of PK by HCO3− cannot be explained entirely by an effect of ionic strength, but probably represents a specific modulator-enzyme interaction. Under similar conditions PEP CK was maximally activated. Although L-lactate inhibited PEP CK (Ki(lac) = 1.8 mM), this effector may play a minor role in regulation of PEP flux. These results implicate the poise of the HCO3− :CO2 system as a major determiner of endproduct accumulation in H. diminuta. |
| تدمد: | 1097-010X 0022-104X |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ef041118b0e90731f14b224a2f2bc1b5 https://doi.org/10.1002/jez.1402000303 |
| حقوق: | CLOSED |
| رقم الأكسشن: | edsair.doi.dedup.....ef041118b0e90731f14b224a2f2bc1b5 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 1097010X 0022104X |
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