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

Myosin isolated under phosphorylation conditions, showed an additional band of phosphorylated light chain. In the case of cardiac myosin, LC2 is the phosphorylated light chain whereas in skeletal myosin, it is the 18,000 dalton component known as DTNB light chain. There are no differences in K+-EDTA and Ca2+ activated myosin ATPase of cardiac and skeletal of control and phosphorylated myosins. Our experiments showed that the rat heart and skeletal muscle myosins isolated under phosphorylating conditions exhibited high phosphate content which is associated with higher actin activated Mg2+ ATPase activity of myosin as compared to control. Control myosin phosphorylated using myosin light chain kinase and Ca2+ also showed high actin activated myosin ATPase activity. Beef heart myosin isolated in the presence of phosphate buffer, also exhibited a higher level of phosphate followed by an increase in actin activation as compared to myosin isolated in the absence of phosphate buffer. All these experimental data suggest that there is a direct relationship between actin activation and the amount of phosphate incorporated as a result of phosphorylation.
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PMID:Phosphorylation and its effects on ATPase activity of cardiac and skeletal myosins. 16 48

When studying enzymic and fluorescence properties of myosin and DTNB-treated myosin in the presence of K+, Na+, Li+, NH4+, Ca2+ and Mg2+ cations the following results were obtained. By the intrinsic protein fluorescence techniques no essential structural changes of myosin molecule at the dissociation of the DTNB light chain and activation myosin ATPase in the presence of different cations were found. The decrease of K+-EDTA-, the increase of Mg2+-activated and the stability of Ca2+-activated myosin ATPase may be the result of the modification of SH1 or SH2 sulfhydryl groups when treating the DTNB myosin in our conditions. The different level of decrease of the K+- and NH4+-activated myosin. ATPase may be explained by the fact, that myosin sulfhydryl groups have different effects on the activation of its ATPase by these cations.
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PMID:[Comparative study of myosin and DTNB-treated myosin with regard to ATP activity and fluorescence]. 97 74

The cation dye acridine orange (AO) was shown to inhibit ATPase activity of myosin, DTNB-myosin and heavy meromyosin and not to influence that of EDTA-S-1 at low ionic force. The inhibiting effect is concerned with the presence of KCl in solution. The allosteric influence of AO on myosin ATPase activity is discussed and dependence of this effect on charge distribution on the surface of the protein molecule is considered.
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PMID:[Acridine orange inhibition of the ATPase activity of myosin and its fragments]. 621 85

The reactivity of thiol groups in cardiac myosin obtained from porcine ventricles was compared with that in rabbit skeletal myosin. 1. The specific thiol group, S2, of cardiac myosin became reactive to N-ethylmaleimide (NEM) upon the addition of Mg2+-ATP or Mg2+-ADP, as in the case of skeletal myosin, although to a lesser degree. Enhancement of the reactivity of S2 resulting from cooperative interaction between F-actin and Mg2+-ATP, but not Mg2+-ADP, which was first found in skeletal myosin, was also observed in cardiac myosin. 2. The total number of 5,5'-dithiobis(2-nitrobenzoate) (DTNB)-reactive thiols decreased in the presence of Mg2+ADP and decreased further in the presence of Mg2+-ATP for both myosins, in contrast to the concomitant increase in the reactivity of S2. The decrement was smaller in cardiac myosin than in skeletal myosin. 3. The DTNB-reactive thiols were classified into three groups with respect to their reactivity. The third or most slowly reacting thiol group, was found to be remarkably susceptible to Ca2+ at physiological concentrations (10(-8)-10(-6) M) in the presence of Mg2+-ADP for cardiac myosin, but in striking contrast, in the presence and relatively long-lived intermediate of myosin ATPase, the structure of which is sensitive to Ca2+, may be different in cardiac and skeletal myosins.
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PMID:Actin-induced local conformational change in the myosin molecule. III. Reactivity of S2 thiol and DTNB-reactive thiols of porcine cardiac myosin. 689 37