A protein factor inhibiting the magnesium-activated adenosine triphosphatase of desensitized actomyosin.
نویسندگان
چکیده
1. The preparation and properties of a myofibrillar protein factor which inhibits the Mg(2+)-activated adenosine triphosphatase of desensitized actomyosin is described. 2. This factor had negligible effect on the Mg(2+)-activated adenosine triphosphatase of natural actomyosin and on the Ca(2+)-activated adenosine triphosphatases of desensitized actomyosin and myosin. 3. The Mg(2+)-activated inosine triphosphatase activity of desensitized actomyosin was not affected by the factor. 4. The inhibitory effect was sensitive to ionic strength. In addition to their ionic effects Mg(2+) and Ca(2+) appeared to have a specific action in reducing the effect of the inhibitor. 5. F-actin reduced the inhibition whereas Bailey-type tropo-myosin had little effect. 6. As far as can be judged from the reported experiments this factor is different from any of the previously described myofibrillar components.
منابع مشابه
The adeonosine-triphosphatase activity of desensitized actomyosin.
1. A simple procedure involving repeated washings of actomyosin, extracted as the complex from myofibrils (natural actomyosin) at ionic strength less than 0.002, is described for the preparation of a desensitized actomyosin. 2. The Mg(2+)-activated adenosine triphosphatase of natural actomyosin was markedly inhibited by ethylenedioxybis(ethyleneamino)tetra-acetic acid, whereas that of the desen...
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It has been reported by several groups of workers that incubation of the relaxing factor granar of muscle with magnesium and adenosine triphosphate results in the formation of a soluble relaxing substance capable of inhibiting the magnesium-activated adenosine triphosphatase activity of myofibrils or actomyosin (3-6) and the contraction of single glycerinated muscle fibers (7). In addition, Uri...
متن کاملStudies on Myofibrillar Adenosine Triphosphatase with Calcium-free Adenosine Triphosphate.
It has been reported by several groups of workers that incubation of the relaxing factor granar of muscle with magnesium and adenosine triphosphate results in the formation of a soluble relaxing substance capable of inhibiting the magnesium-activated adenosine triphosphatase activity of myofibrils or actomyosin (3-6) and the contraction of single glycerinated muscle fibers (7). In addition, Uri...
متن کاملThe relaxing protein system of striated muscle. Resolution of the troponin complex into inhibitory and calcium ion-sensitizing factors and their relationship to tropomyosin.
1. A method involving isoelectric precipitation and chromatography on SE-Sephadex (sulphoethyl-Sephadex) is described for the preparation of the troponin complex free of tropomyosin from low-ionic-strength extracts of natural actomyosin and myofibrils. 2. Purified troponin complex required tropomyosin to inhibit the Mg(2+)-stimulated adenosine triphosphatase activity and superprecipitation of d...
متن کاملThe effect of actin on the magnesium-activated adenosine triphosphatase of heavy meromyosin.
The evidence is now strong that magnesium plays an important role in the interactions between myosin, actin and ATP which are associated with the physiological activity of muscle. Although calcium activates the adenosine triphosphatase ofboth L-myosin and isolated myofibrils, in the presence of this cation alone neither contraction (Ashley, Arasimavicius & Hass, 1956) nor relaxation (Bendall, 1...
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ورودعنوان ژورنال:
- The Biochemical journal
دوره 104 3 شماره
صفحات -
تاریخ انتشار 1967