Creatine kinase in regulation of heart function and metabolism. I. Further evidence for compartmentation of adenine nucleotides in cardiac myofibrillar and sarcolemmal coupled ATPase-creatine kinase systems
| Autor: | A.N. Preobrazhensky, I.V. Emelin, Z. A. Huchua, Renée Ventura-Clapier, V.A. Saks |
|---|---|
| Rok vydání: | 1984 |
| Předmět: |
medicine.medical_specialty
Pyruvate dehydrogenase kinase ATPase Pyruvate Kinase PKM2 Creatine Phosphocreatine chemistry.chemical_compound Adenosine Triphosphate Sarcolemma Myofibrils Adenine nucleotide Internal medicine medicine Animals Molecular Biology Creatine Kinase Adenosine Triphosphatases biology Adenine Nucleotides Myocardium Rats Inbred Strains Cell Biology Rats Adenosine Diphosphate Kinetics Endocrinology chemistry Biochemistry biology.protein Creatine kinase Rabbits Pyruvate kinase |
| Zdroj: | Biochimica et biophysica acta. 803(4) |
| ISSN: | 0006-3002 |
| Popis: | In isolated and purified cardiac myofibrillar and sarcolemmal preparations, the route of movement of ADP produced in the Mg2+-ATPase reactions was studied by investigating the efficiency of competition between the endogenous creatine kinase and exogenous pyruvate kinase reactions. In the homogeneous control system composed of hexokinase and glucose as ATPase, soluble creatine kinase rapidly rephosphorylated ADP produced in the presence of 1 mM ATP, but the addition of pyruvate kinase in an increasing amount inhibited the reaction of creatine release from phosphocreatine and symmetrically increased the rate of pyruvate production from phosphoenol pyruvate. At a pyruvate-kinase/creatine-kinase activity ratio (PK/CK) of 50, all ADP was used by the pyruvate kinase. In myofibrillar and sarcolemmal preparations containing particulate creatine kinase, the creatine kinase reaction was much less efficiently suppressed by pyruvate kinase, and at PK/CK = 50 half-maximal release of creatine was still observed. The rate of immediate myofibrillar MgADP rephosphorylation in the endogenous creatine-kinase reaction was observed to be governed by the concentration of phosphocreatine in accordance with the kinetics of this enzyme. The physiological significance of these findings is discussed. |
| Databáze: | OpenAIRE |
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