Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Ca2+-dependent regulation of smooth muscle actomyosin involves a myosin light chain kinase (ATP: myosin light chain phosphotransferase). It has been shown (Dabrowska, R., Aromatorio, D., Sherry, J.M.F., and Hartshorne, D.J. 1977, Biochem. Biophys. Res. Commun. 78, 1263) that the kinase is composed of two proteins of approximate molecular weights 105 000 and 17 000. In this communication it is demonstrated that the 17 000 component is the modulator protein. This conclusion is based on: (1) the identical behavior of the 17 000 kinase component and modulator protein in assays of actomyosin Mg2+-ATPase activity, phosphorylation of myosin, and phosphodiesterase activity, and, (2) the similarity of the 17 000 kinase component and the modulator protein with respect to amino acid composition, absorption spectrum, and electrophoresis in urea-polyacrylamide gels. It is shown also that the modulator protein from smooth muscle and troponin C are distinct proteins.
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PMID:Modulator protein as a component of the myosin light chain kinase from chicken gizzard. 20

The activity of enzymes transporting calcium across the membrane of the muscle fibre and sarcoplasmic reticulum was studied. The activity of actomyosin Mg2+-ATPase and the composition of troponin were investigated also. In seven Pietrain pigs halothane alone or with suxamethonium induced the malignant hyperthermia syndrome. In the animals with malignant hyperthermia Ca2+-ATPase was not activated in the plasma membranes of the muscle fibres, when compared with control animals (n = 4). An increase of Ca2+-ATPase of the sarcoplasmic reticulum was observed in animals with malignant hyperthermia; the opposite was noted in the control group. No significant changes in the activity of Mg2+-ATPase of the sarcoplasmic reticulum and of Mg2+-ATPase of actomyosin were observed after exposure to halothane in control pigs and those with malignant hyperthermia. The amount of troponin C was significantly changed in the animals with malignant hyperthermia. The mechanism of the development of malignant hyperthermia syndrome is discussed.
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PMID:Experimental porcine malignant hyperthermia: the activity of certain transporting enzymes and myofibrillar calcium-binding protein content in the muscle fibre. 612 63

On treatment with 10 mM EDTA at 30 degrees C, protein of 18,000 daltons was released from myofibrils, thin filaments and myosin B prepared from the smooth muscle of an ascidian, Halocynthia roretzi. This protein was purified from the EDTA extract of myofibrils by differential centrifugation, freeze-drying and gel-filtration. Based on its molecular weight, electrophoretic mobilities in the presence and absence of Ca2+ and other properties, it was identified as troponin C. By EDTA treatment, ascidian myosin B lost the Ca2+-sensitivity of Mg2+-ATPase, and EDTA-treated myosin B recovered the sensitivity by mixing with the EDTA extract of myosin B in the presence of Mg2+. Gel-electrophoretic patterns indicated that desensitization and resensitization of ascidian myosin B were accompanied by the removal and binding of troponin C. These results indicate that ascidian smooth muscle is regulated by a troponin-tropomyosin system, and desensitization induced by EDTA treatment is due to the removal of troponin C but not the release of the light chains of the myosin molecule. Based on these findings, we have established a simple method for the purification of troponin C from ascidian smooth muscle.
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PMID:Removal of troponin C and desensitization of myosin B from ascidian smooth muscle by treatment with ethylene diamine tetraacetate. 623 Dec 81