Reversible MM-creatine kinase binding to cardiac myofibrils
| Autor: | C. Lauer, Renée Ventura-Clapier, G. V. Elizarova, Guy Vassort, Valdur Saks |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
medicine.medical_specialty
Physiology macromolecular substances In Vitro Techniques Phosphocreatine chemistry.chemical_compound Myofibrils Adenine nucleotide Internal medicine medicine Animals Papillary muscle Creatine Kinase chemistry.chemical_classification biology Adenine Nucleotides Myocardium Histological Techniques Cell Biology Metabolism musculoskeletal system Myocardial Contraction Biomechanical Phenomena Rats Isoenzymes Enzyme medicine.anatomical_structure Endocrinology chemistry Circulatory system biology.protein Creatine kinase Calcium Myofibril |
| Zdroj: | The American journal of physiology. 253(3 Pt 1) |
| ISSN: | 0002-9513 |
| Popis: | Skinned rat papillary muscles and purified preparations of rat cardiac myofibrils were used to study the nature of the interaction of creatine kinase with cardiac myofibrils. High activity of creatine kinase (2 IU/mg protein in fibers and 0.9 IU/mg in purified myofibrils) was due mostly to reversibly bound enzyme. This activity could be removed and rebound. The process of creatine kinase rebinding was characterized by apparent Km value of 0.14 mg/ml (approximately equal to 2 X 10(6) M). Rebinding of creatine kinase to cardiac myofibrils restored the phenomenon of functional compartmentation of adenine nucleotides in myofibrillar space and restored the ability of phosphocreatine to decrease the rigor tension in the presence of MgADP. The physiological experiments with quick length changes showed that rebinding of creatine kinase to skinned papillary muscle also restored Ca sensitivity, increased maximal tension development, decreased stiffness, and restored the tension recovery after quick length changes in muscle under condition of inhibition of endogenous creatine kinase by 1-fluoro-2,4-dinitrobenzene. It is concluded that creatine kinase reversibly bound to cardiac myofibrils is involved in the energy supply for cardiac contraction. |
| Databáze: | OpenAIRE |
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