Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.4.1 (myosin ATPase)
 1,140 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Experiments were carried out to examine the biochemical changes, such as contractile protein biochemistry and membrane bound enzyme alterations associated with skeletal muscles of myd/myd. 2. Our studies demonstrate that there was a progressive decline in myofibrillar ATPase activity, and this decrease is greatest in 30 weeks old animals of myd/myd as compared to controls. 3. The proteolytic activity of myofibrils isolated from myd/myd was significantly higher than controls. 4. There was no significant difference in Ca2+ ATPase activity of myosin and actin-activated myosin ATPase activity of myd/myd and their controls. 5. Mg2+ ATPase and Na(+)+K(+)-ATPase of myodystrophic SL showed significant increase compared to controls. 6. Isoproterenol stimulated adenylate cyclase activity was significantly lower in the SL of dystrophic mice compared to controls. 7. GTP+isoproterenol stimulate adenylate cyclase was significantly higher in control SL and SR when compared to SL and SR isolated from myd/myd. 8. Guanylate cyclase activity was greater in myodystrophic mice both in the absence and presence of Triton X-100. cGMP and cAMP phosphodiesterase activities were greater in dystrophic mice as compared to controls. 9. These observations suggest that there are significant changes in myofibrillar ATPase, myofibrillar protease and membrane bound enzymes of myd/myd compared to control.
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PMID:Myofibrillar and membrane-bound enzymes in skeletal muscle from myodystrophic mice. 135 51

Calcium-independent regulation of the contractile proteins of cardiac muscle has been studied using hyperpermeable cells from rat ventricles and sections of quickly frozen rat hearts. These preparations have been used to study maximum Ca-activated force, myosin ATPase activity and the maximum velocity of unloaded shortening. Beta adrenergic activity increases the amount of force and the ATPase activity in accordance with the concentration of the V1 isozyme of myosin. V3 activity is decreased at the same time. In tissues containing only V1, there is no change in maximum velocity in response to beta adrenergic stimulation. These results indicate that beta adrenergic stimulation recruits V1 force generators and probably regulates a transition between a Ca unresponsive and a Ca responsive force generator. A 21,000 dalton protein that reproduces the effect of beta adrenergic stimulation on myosin has been isolated.
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PMID:Ca-independent regulation of cardiac myosin. 297 Feb 4

Eugenol (EUG) acts as a calcium antagonist but effects on the contractile proteins could also occur. We investigated inotropic effects of EUG in rat left ventricular papillary muscles, measuring isometric force, time variables, and post rest potentiation and EUG actions on the effects of Ca2+ (0.62 to 2.5 mM) and isoproterenol (5 ng/ml), on myosin ATPase activity and on the calcium currents in single ventricular myocytes. EUG reduced tension and time variables without altering the sarcoplasmic reticulum activity increasing post-pause relative potentiation. Isoproterenol and Ca2+ counteract these negative inotropic effects. Tetanic tension diminished, but not the myosin ATPase activity suggesting an isolated sarcolemmal effect. EUG 0.1 mM decreased the Ca2+ current amplitude in the entire potential range tested and 0.5 mM almost completely blocked this inward current. Results suggested that EUG depresses force without affecting the contractile machinery and its action is the only dependent blockade of the calcium inward current.
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PMID:Effects of eugenol, an essential oil, on the mechanical and electrical activities of cardiac muscle. 1555 Jul 89