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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)

Antibodies prepared against actomyosins can be shown to behave similarly, if not identically to more recently prepared antibodies against highly purified myosins. Details of the purification of the antigens, and of the production of antibodies to chick myosins from smooth gizzard muscle and from striated pectoral muscle are given. The antibody specificity appears to be directed against the heavy chains of the myosin molecules, since these antibodies specifically inhibit the myosin ATPase reaction, and since in situ staining of myosin polypeptide chains on an SDS gel using the antibodies in indirect fluorescence shows staining only in the heavy band region. Use of the antibodies in immunofluorescence microscopy suggest that the antibodies are tissue, but not species, specific. Example of their use in staining tissue sections are shown.
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PMID:Production of specific antibodies to contractile proteins, and their use in immunofluorescence microscopy. I. Antibodies to smooth and striated chicken muscle myosins. 5 8

Heart myosin ATPase (measured with 10 mM CaCl2, and 0.60 M KCl) was found to be higher in rats (423 nmoles of Pi/min/mg) than in guinea-pig (268 nmoles of Pi/min/mg), dogs (139 nmoles of Pi/min/mg) or rabbits (94 nmoles of Pi/min/mg). Rat heart myosin ATPase was found to be higher than that from a pure red skeletal muscle myosin (soleus from guinea-pig: 286 nmoles/min/mg) and only one third lower than that from fast skeletal muscle myosin from rabbits. The heart myosin ATPase from rat, guinea-pig, and rabbit correlates with the maximum velocity of shortening at zero load of the myocardial muscle, as determined by other authors. These four cardiac muscle myosins have the same two light subunits (M.W.: 27000 and 18000) in SDS polyacrylamide gel electrophoresis; one of them (M.W.: 18000) exists in guinea-pig and dog as two different molecules having a different charge, as shown in urea electrophoresis, but in the rat, this subunit is also unique in urea gel electrophoresis. Rat heart, apparently, does not possess the phosphorylated light subunit (M.W.: 18,000) described by others in rabbit heart myosin. Attempts have been made to obtain a highly purified myosin, but this procedure does not suppress the striking difference which exists between rat and dog heart myosin ATPase.
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PMID:A comparative study of heart myosin ATPase and light subunits from different species. 12 4

The immunogenicity of smooth muscle actin is increased by ageing at 4 degrees for at least a week. Rabbits lacking natural smooth muscle antibodies were injected with 1 mg of aged purified actin in adjuvant. Fourteen out of thirty-six rabbits produced serum antibodies which precipitated with actin solution, but not with smooth muscle tropomyosin, myosin, light or heavy meromyosin or with other unidentified non-actin proteins in crude extracts. Analysis of crude actin extract before and after precipitation by antiserum (i) by Sephadex G-200 chromatography and (ii) for its stimulating effect on myosin ATPase activity showed that actin was selectively removed. The precipitate itself, analysed on SDS-polyacrylamide gel, showed one band in the actin position, and otherwise only bands representing immunoglobulins. The antiserum also inhibited the ability of actin to stimulate myosin ATPase activity, and prevented polymerization of G-actin to F-actin, as shown by viscosity and EM studies. On immunoflouresence with cryostat tissue sections or cell cultures, anti-actin serum stained smooth muscle fibres and many non-muscle cells, in the latter staining the microfilaments. The staining was prevented by absorbing the antiserum with actin (16 mug per 5 mul serum), and was abolished by pretreatment of the cells with cytochalasin B. No species specificity was demonstrated for these anti-actin antibodies.
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PMID:The specificity of anti-actin serum. 13 24

Single muscle fibres were isolated by microdissection from freeze-dried samples of rabbit psoas and soleus muscles. The individual fibres were typed according to qualitative histochemical reactions for succinate dehydrogenase or NADH-tetrazolium reductase and for alkaline Ca2+-activated myofibrilla myosin ATPase after acid or alkaline preincubation. Methods are described for electrophoretic analysis by means of polyacrylamide disc electrophoresis in the presence of SDS of total myofibrilla proteins in single fibres after pre-extraction of soluble proteins. Fast-twitch white fibres revealed a myosin light chain pattern characteristic of "fast- type" myosin with three light chains of apparent molecular weights of 22,300 (LC1) 18,400 (LC2) and 16,000 (LC3). Fast-twitch red fibres were indistinguishable in this respect from fast-twist white fibres and showed an identical pattern of myosin light chains. Slow-twitch fibres could be characterized by a myosin light chain pattern typical of myosin of slow-twitch muscles with peptides of the apparent molecular weights of 23,500 (LC1Sa), 23,000 (LC1Sb) and 18,500 (LS2S). Slow-twitch fibres isolated from soleus as well as from psoas muscle were indistinguishable with regard to their myosin light chain patterns, thus suggesting that fibres of the same histochemical type correspond in their myosin light chain patterns irrespective of their origin from different muscles.
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PMID:Myosin light chain patterns of individual fast and slow-twitch fibres of rabbit muscles. 14 18

Human cardiac myosin isolated from operatively obtained samples of ventricular septum and left ventricular free wall of patients with asymmetric septal hypertrophy (ASH) was compared, with respect to structural and enzymatic properties, to myosin isolated from hearts of patients without heart disease. The following parameters were studied: 1) activation of myosin ATPase activity by K+-EDTA and Ca2+,2) molecular weight of the heavy and light chains of myosin as determined by electrophoretic migration in SDS-polyacrylamide gels, and 3) ability to form bipolar aggregates at low ionic strength, as examined by electron microscopy. No difference was present in any of these parameters between human cardiac myosin from patients with ASH and from patients without heart disease. Thus, the genetic defect present in patients with ASH is not expressed in the particular structural and functional characteristics of myosin evaluated in this study.
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PMID:Characterization of myosin from patients with asymmetric septal hypertrophy. 14 40

Myosin was purified from the flight muscles of a flying (pigeon) and a nonflying (fowl) bird. Ki (ADP) of myosin ATPase of pigeon is higher, but the Km (ATP) is lower than that of fowl. The specific activity (mumole of Pi liberated/min/mg protein) is higher for the fowl. A0.5 (CaCl2) of myosin of both pigeon and fowl is similar. However, the two proteins differ in their interactions with ADP, ATP and p-chloromercuribenzoate. The two proteins have the same tyrosine, tryptophan and sulfhydryl contents. The electrophoretic patterns of the two myosins on SDS-polyacrylamide gels are different. These studies show significant molecular differences in the myosin derived from the flight muscles of a flying (pigeon) and a nonflying (fowl) bird.
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PMID:Comparative studies on myosin ATPase of a flying and nonflying bird. 15 58

Hypertrophy of the urinary bladder was produced in rabbit by partial ligation of the urethra. Electrophoresis of the bladder smooth muscle myosin on highly porous (3.5-7% gradient) SDS-polyacrylamide gel revealed two heavy chain isoforms, SM-1 and SM-2 with approximate molecular weights of 204,000 and 200,000, respectively. The ratio of the SM-2 to SM-1 heavy chain is 3:1 for myosin isolated from normal bladder smooth muscle, and this ratio changes to about 1:1 in hypertrophied bladder. Despite a change in the ratio of SM-2 to SM-1, the myosin ATPase and the actin-activated ATPase activities are not altered in response to hypertrophy.
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PMID:Smooth muscle myosin isoform distribution and myosin ATPase in hypertrophied urinary bladder. 153 95

Carbonic anhydrase (CA III) and myoglobin contents from isolated human muscle fibers were quantified using a sensitive time-resolved fluoroimmunoassay. Human psoas muscle specimens were freeze-dried, and single fibers were dissected out and classified into type I, IIA and IIB by myosin ATPase staining. Fiber typing was further confirmed by SDS-PAGE. CA III and myoglobin were found in all fiber types. Type I fibers contained higher concentrations of CA III and myoglobin than type IIA and IIB fibers. The relative concentrations of CA III in type IIA and IIB fibers were respectively 24% and 10% of that in type I fibers. The relative concentrations of myoglobin in type IIA and IIB fibers were 60% and 28% of that in type I fibers. Anti-CA III immunoblotting results from fiber-specific pooled samples agreed well with quantitative measurements. The results indicate that CA III is a more specific marker than myoglobin for type I fibers.
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PMID:Quantification of carbonic anhydrase III and myoglobin in different fiber types of human psoas muscle. 153 17

The morphology and function of actin in cultured bovine retinal pigment epithelial (RPE) cells were studied. Filamentous actin was identified with a fluorescent mushroom toxin, nitrobenzoxadiazole (NBD)-phallacidin, specific for actin. Dark-field microscopy of cultured RPE cells revealed numerous pigment granules; fluorescent microscopy identified scattered lipofuscin granules. One-dimensional SDS polyacrylamide gel electrophoresis of urea-soluble proteins extracted from RPE cells showed a 46,000-dalton protein band which comigrated with authentic muscle actin. Densitometric scanning showed that this protein band comprised 7.6% of the total urea-soluble proteins. An actin-activated skeletal-muscle myosin Mg-ATPase assay, using skeletal-muscle heavy meromyosin as enzyme and [gamma-32P]-ATP as substrate, demonstrated functional actin in RPE cell extracts after DEAE-cellulose anion exchange chromatography. The actin-containing protein fractions were eluted at ionic strengths between 0.19 and 0.36 M KCl. The activation of myosin ATPase by actin in RPE cells provides a molecular basis for the phagocytic activity which is important in maintaining the integrity of retinal photoreceptor cells.
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PMID:Activation of Mg-ATPase of skeletal-muscle myosin by bovine retinal pigment epithelial actin. 253 75

The fiber type composition of two fast muscles of the chicken, namely, adductor superficialis (AS) and pectoralis major (PM) was examined by the histochemical myosin ATPase staining and immunochemical techniques using monoclonal antibodies (McAbs). Two new McAbs produced against the myosin of the anterior latissimus dorsi (ALD) muscle of the chicken and named ALD-122 and ALD-83 were characterized to be specific for myosin heavy chain (MHC) and for myosin light chain-1 respectively. They were used in conjunction with previously reported McAbs specific for slow MHC (ALD-47), fast MHC (MF-14) and fast light chain-2 (MF-5). By the histochemical ATPase test most muscle fibers of AS and PM muscles reacted as IIA and IIB respectively. By immunofluorescent staining with the anti-MHC McAbs, ALD-122 and MF-14, the fibers of AS muscle showed remarkable heterogeneity whereas PM muscle fibers reacted uniformly. Differences in the myosin light chain composition of AS and PM muscles were also found by SDS-gel electrophoresis and immunoblot analysis with the anti-light chain McAb, ALD-83. The study clearly indicated that the histochemically homogenous (type IIA) AS muscle is composed of several subpopulations of fibers which differ in their myosin composition and that this heterogeneity of the muscle is not simply due to presence of variable amounts of slow myosin in its fibers.
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PMID:Heterogeneity of fast-oxidative muscle fibers of chicken demonstrated by anti-myosin monoclonal antibodies. 273 24


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