共查询到20条相似文献,搜索用时 31 毫秒
1.
Catherine Devine Strader Elias Lazarides Michael A. Raftery 《Biochemical and biophysical research communications》1980,92(2):365-373
SDS-polyacrylamide gel electrophoresis of acetylcholine receptor from electroplax membrane fragments shows, in addition to the four receptor subunits of 40,000, 50,000, 60,000 and 65,000 daltons, other components of apparent molecular weights 43,000, 47,000 and 90,000 daltons. In this study deoxyribonuclease I inhibitory activity has been used to identify actin in receptor-enriched membranes and affinity chromatography on a deoxyribonuclease I agarose column has been used to purify this protein from the membrane preparations. In addition the membrane protein components have been analyzed by electrophoresis on a series of SDS-polyacrylamide gels of varying acrylamide concentrations. Evidence is presented that actin is a component of most preparations of receptor-enriched membrane fragments, having an apparent molecular weight of 47,000 daltons, and is distinct from the 43,000 dalton protein. 相似文献
2.
J D Irvin J D Robertus A F Monzingo 《Biochemical and biophysical research communications》1977,74(2):775-779
An anti-viral enzyme from , known to inhibit protein synthesis has been crystallized in a form useful for high resolution x-ray diffraction studies. Cracking of crystals due to the introduction of heavy metals can be reduced by cross linking with glutaraldehyde using a rapid fixation method. Several apparent isomorphous heavy metal derivatives of the crystal have been found. The molecular weight of the protein has been reevaluated as 31,000 daltons. 相似文献
3.
4.
E.C. Hatchikian 《Biochemical and biophysical research communications》1981,103(2):521-530
A cobalt-porphyrin containing protein has been isolated from the sulfate-reducer (Norway). This violet-colored protein has a molecular weight of approx. 13,000 daltons and contains 1 cobalt atom/molecule. The apo-protein was estimated to contain 104 amino-acid residues giving a molecular weight of 11,000 daltons. The UV-visible absorption spectrum of the protein exhibiting maxima at 588,418 and 280 nm with a shoulder at 550 nm is characteristic of metalloporphyrin proteins. The molar extinction coefficients of the cobalt-protein at 588, 418 and 280 nm are 31,330 , 64,670 and 17,200 respectively and its absorbance ratio is 0.54. The protein is reduced by dithionite giving a blue-colored reduced form. Important spectral modifications of the chromophore occurred during the reduction including a shift of the Soret peak from 418 to 381 nm and a shift of the α band in the opposite direction from 588 to 593.5 nm. The Co-protein was slowly reduced by the hydrogenase from under hydrogen in the presence of cytochrome C3. The reported data suggest that the redox states of the cobalt center of this new electron carrier correspond to the Co(III) and Co(II) states. 相似文献
5.
Anti-clotting activity of endothelial cell cultures and heparan sulfate proteoglycans 总被引:4,自引:0,他引:4
A photoaffinity probe for the vitamin D-dependent chick intestinal calcium binding protein (CaBP) has been prepared by conjugation of methyl-4-azidobenzoimidate (MABI) to lactoperoxidase-125I-iodinated CaBP to yield 125I-CaBP-MABI: [3 moles MABI per mole CaBP]. After incubation of 125I-CaBP-MABI (28,000 daltons) in model systems with bovine intestinal alkaline phosphatase (AP) (67,000 daltons), a UV light-dependent crosslinking occurred to yield a conjugate with a molecular weight of 95,000 (by SDS-gel electrophoresis); no crosslinking occurred with alkaline phosphatase. The formation of the 125I-CaBP-MABI-AP was found to occur only in the presence of calcium. 相似文献
6.
J Patrick J Boulter J C O'Brien 《Biochemical and biophysical research communications》1975,64(1):219-225
Acetylcholine receptor has been purified from in the presence of the serine protease inhibitor phenylmethyl sulfonyl flouride. The purified material has a specific toxin-binding capacity of 3.6 nmoles of toxin per mg of protein. Electrophoresis of reduced, dissociated receptor on acrylamide gels containing sodium dodecyl sulfate reveals components of 110,000, 60,000, 54,000, and 48,000 daltons. No component with an apparent molecular weight of less than 48,000 daltons is seen. Limited digestion of this preparation with trypsin results in the appearance of components of 44,000 and 42,000 daltons. Prolonged digestion with trypsin generates species with apparent molecular weights of less than 42,000 and has no effect on the specific protectable toxin-binding capacity of the preparation. 相似文献
7.
Chromatin protein kinases and phosphoproteins during myoblast growth and differentiation 总被引:1,自引:0,他引:1
M P Leibovitch L Tichonicky J Kruh 《Biochemical and biophysical research communications》1978,81(2):623-629
A photolabile derivative of α-bungarotoxin which binds specifically to acetylcholine receptor has been used to investigate the topography of the membrane associated protein. It is shown that the toxin can be crosslinked to a polypeptide of 40,000 daltons, to which it is known to bind, and in addition to another polypeptide of 65,000 daltons which is a major constituent of the membrane. The results substantiate the notion that this nicotinic acetylcholine receptor is composed of different polypeptides and that some of these interact with each other or are in close proximity on the exterior surface of the post-synaptic membrane. 相似文献
8.
Haruko Meyer Justus Mueller Franz Meyer 《Biochemical and biophysical research communications》1978,82(3):834-839
An acyl-CoA carboxylase, which catalyzes the carboxylation of acetylpropionyl-, and butyryl-CoA, has been isolated from the tapeworm . The enzyme has an absolute requirement for ATP, Mg2+, and HCO3 and, in addition, requires K+ for full catalytic activity. The enzyme has been purified 50-fold by a combination of calcium phosphate gel adsorption, ion-exchange column chromatography, and gel filtration. In its substrate specificity, K+ requirement, molecular size, and antigenic behavior, the tapeworm enzyme is similar to the acyl-CoA carboxylase of another helminth— the free-living nematode . 相似文献
9.
Favin, a crystalline lectin from Vicia faba 总被引:2,自引:0,他引:2
A lectin from the fava bean (Vicia faba) has been purified and crystallized in a form suitable for high-resolution crystallographic structure analysis. This protein binds glucose- and mannose-like saccharides, and it is mitogenic for lymphocytes. The fava lectin crystallizes in the orthorhombic space group. P212121 with unit cell dimensions . The mass of protein in the asymmetric unit is 53,000 daltons, corresponding to the molecular weight of the protein in solution. 相似文献
10.
Cytoplasmic free and bound polysomes were isolated from bovine adrenal cortex, and used to program protein synthesis in rat liver cell sap and wheat germ lysate systems. Synthesis of adrenodoxin(Ad) and adrenodoxin reductase(AdR) in the cell-free systems was determined by immunoprecipitation using monospecific antibodies, and the sizes of the products were analyzed by SDS-polyacrylamide gel electrophoresis. Ad was synthesized by both free and bound polysomes as a putative large precursor having molecular weight of approximately 20,000 daltons, which was processed to mature size Ad (MW 12,000 daltons) by incubation with adrenal cortex mitochondria. On the other hand, AdR was synthesized only by free polysomes apparently as the mature size product. 相似文献
11.
Absence of ferric enterobactin receptor modification activity in mutants of Escherichia coli K-12 lacking protein a. 总被引:1,自引:0,他引:1
E H Fiss W C Hollifield J B Neilands 《Biochemical and biophysical research communications》1979,91(1):29-34
The modification activity for the ferric enterobactin receptor in the Triton X-100 solubilized outer membrane of K-12 was adsorbed to a column of -aminobenzamidine-//-sepharose and eluted with free benzamidine. Recombination of the dialyzed eluate with the filtrate from the column reinstituted conversion of the receptor from 81K to 81K1, the latter exhibiting an apparent molecular weight of 74,000 daltons in sodium dodecyl sulfate polyacrylamide gel analysis. The eluate from the -aminobenzamidine column was shown to contain a component, coincident on gels with both protein and modification activity, which by mutational and other analyses appears to be identical with protein of the outer membrane. 相似文献
12.
A. Ian Scott S.L. Lee W. Wan 《Biochemical and biophysical research communications》1977,75(4):1004-1009
The “ajmalicine synthetase” system of has been partially purified from callus, seedlings and mature plants. On gel filtration of the cell-free extract, four β-D-glucosidase isozymes were observed in seedlings and plants. Only two were present in the callus. A protein peak at 55,000 daltons in all three materials was capable of synthesizing ajmalicine from tryptamine and secologanin in the presence of NADPH. This “ajmalicine synthetase” rapidly lost its ability to synthsize ajmalicine, but retained the β-glucosidase activity. 相似文献
13.
Y D Karkhanis R L Anderson J Y Zeltner R Z Maigetter D J Carlo T H Stoudt 《Biochemical and biophysical research communications》1979,89(2):750-758
An antigenic subunit of molecular weight 66,000 daltons has been isolated from the antigenic complex of the Melvin strain of . Incubation of the complex in 8M urea at room temperature for four hours resulted in the dissociation of the subunit from the complex. It was separated from the complex by chromatography of the incubation mixture on a Sepharose 6B column in 50 mM ammonium bicarbonate pH 8.5 without 8M urea and further purified by affinity chromatography. This communication reports on a newly isolated antigenic protein devoid of LPS present in the bacteria. 相似文献
14.
H P Moore P R Hartig W C Wu M A Raftery 《Biochemical and biophysical research communications》1979,88(2):735-743
Rapid efflux of 22Na from within closed vesicles derived from electroplax membranes has been studied as an assay of acetylcholine receptor functionality. The most highly purified membrane preparations contained major polypeptides of M.W. 43 and 90 × 103 daltons in addition to the four peptides characteristic of the acetylcholine receptor (40, 50, 60, 65 × 103 daltons). Removal of these extra peptides by base extraction did not significantly alter the characteristics of carbamylcholine induced 22Na efflux: the agonist dose response curve was similar, preequilibration with agonist caused desensitization, the irreversible antagonist α-Bungarotoxin blocked the efflux and the reversible blockade by the neurotoxin perhydrohistrionicotoxin was also retained. The dose response curve for perhydrohistrionicotoxin corresponded closely to its known binding characteristics for base extracted membranes. 相似文献
15.
Robert B. Trimble Frank Maley 《Biochemical and biophysical research communications》1977,78(3):935-944
Endo-β-N-acetylglucosaminidase H from can be useful in determining both the molecular weight of the protein moiety of glycoproteins and their inherent number of oligosaccharide chains. In the case of carboxypeptidase Y the molecular mass of the carbohydrate free protein was confirmed as 51,000 daltons. The native enzyme was shown to contain 4 oligosaccharide chains each averaging about 14 mannose residues. On treatment of mung bean nuclease I with the endoglycosidase, the molecular mass decreased from 39,000 to 31,000 daltons. The peptides produced on reduction of this enzyme with thiol were 18,700 and 12,500 daltons, indicating that carbohydrate had been present on both. Penicillium nuclease P1 was decreased in size from 40,000 to 30,000 daltons by the endoglycosidase. Although most of the carbohydrate was removed from each of the native enzymes by the endoglycosidase, denaturation of the glycoproteins was necessary to effect complete removal. Enzyme activitywas not affected by carbohydrate depletion of these glycoproteins, a result consistent with similar studies on other oligosaccharide-containing enzymes. 相似文献
16.
Molecular characterization of a stable Flac plasmid 总被引:2,自引:0,他引:2
F L Macrina E Balbinder A Bassel 《Biochemical and biophysical research communications》1973,54(2):737-743
FS is a thermostable extrachromosomal element isolated in which is altered in its replication as compared to its precursor Fts114. Sedimentation of both these plasmids in alkaline sucrose gradients has indicated a difference in their sizes. Contour length measurements of open circular plasmid DNA molecules photographed in the electron microscope have revealed the estimated molecular weight of Fts114 to be 81 × 106 daltons while that of FS is 109 × 106 daltons. FS may carry a segment of chromosomal or cryptic plasmid DNA. 相似文献
17.
Cryptic plasmid in Bacillus pumilus ATCC 7065 总被引:8,自引:0,他引:8
Approximately 2% of the deoxyribonucleic acid (DNA) extracted from ATCC 7065 can be isolated as covalently closed, circular duplex molecules. The 7065 plasmid-like DNA appears homogeneous with respect to size and has a molecular weight of approximately 6 million daltons. A biological function for this circular DNA element has not been determined. 相似文献
18.
Identification of the regulatory subunit of a cAMP-dependent protein kinase in Dictyostelium discoideum 总被引:4,自引:0,他引:4
B H Leichtling I H Majerfeld D S Coffman H V Rickenberg 《Biochemical and biophysical research communications》1982,105(3):949-955
The occurrence of a cytosolic cAMP-binding protein of an approximate molecular weight of 41,000 daltons was monitored in vegetative and developing amoebae of by the use of the photoaffinity probe (32P) 8N3-cAMP. There was a large apparent increase in the amount of this binding protein during development; its molecular weight remained constant, if appropriate methods were employed for the disruption of the amoebae. Comigration during electrophoresis on two-dimensional gels identifies this cAMP-binding protein, photoaffinity-labeled in crude extracts, as the regulatory subunit of the cAMP-dependent protein kinase of . 相似文献
19.
E.C. Hatchikian M. Bruschi N. Forget M. Scandellari 《Biochemical and biophysical research communications》1982,109(4):1316-1323
A ferredoxin has been isolated from the methanogenic organism (strain Fusaro). The protein appears to be constituted by two identical subunits of molecular weight approx. 6000 daltons. The UV-visible spectrum of the protein is characterized by two broad absorption peaks centered at 410 and 300 nm and an absorbance ratio . The molar extinction coefficients at 410 and 300 nm are 36,500 and 45,625 M?1 cm?1, respectively. The amino acid compsition of ferredoxin shows a preponderance of acidic residues and lacks five amino acids. The protein contains 8 cysteine residues and approx. 7 iron atoms and 7–8 acid-labile sulfide groups per molecule which are indicative of the presence of two iron-sulfur clusters in the molecule. The N-terminal sequence shows a high degree of homology with the sequences of ferredoxins from and ferredoxin functions as an electron carrier in the pyruvate dehydrogenase system. Its possible role in a variety of electron transfer reactions is discussed. 相似文献
20.
J J Moura I Moura M Bruschi J Le Gall A V Xavier 《Biochemical and biophysical research communications》1980,92(3):962-970
A protein which contains a cobalt porphyrin was isolated from the sulfate reducer Desulfovibrio gigas. This protein has a molecular weight of approximately 16,700 daltons and is acidic, having an iso-electric point at 3.7. The N-terminal residue was shown to be threonine, and a cobalt analysis gave 0.8 cobalt atoms/molecule, suggesting the presence of a single prosthetic group. The protein has a violet color with absorption bands typical of a metal porphyrin center with maxima at 420 nm, 580 nm with a shoulder at 550 nm. The ratio is 2.1. The protein has no electron paramagnetic resonance (e.p.r.) spectrum, and as the visible spectrum suggests, it probably contains diamagnetic CoIII porphyrin. However the cobalt centre appears to be protected from reduction by sodium dithionite or sodium borohydride. Attmpts at ligand substitution with strong nucleophiles such as CN, causes a slight spectral shift to higher wavelenghts. The cobalt porphyrin can be extracted from the protein with an acidified acetone solution, indicating that it is not covalently bound to the protein. 相似文献