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1.
The sulfated glycopeptides in ovomucin, chalazae and yolk membrane were isolated from the proteolytic digests by gel filtration on a Bio-Gel P-100 column and DEAE-Sephadex A-25 column chromatography. These sulfated glycopeptides contained N-acetylhexosamine (23.3-26.8%), hexose (23.6-24.4%), sialic acid (11.2-18.0%), sulfate (5-12.1%) and peptide (17.5-18.1%). The sulfate contents of glycopeptides in chalazae and yolk membrane were much higher than those in ovomucin, about two times in a molar ratio to hexosamine. The sedimentation patterns of each sulfated glycopeptide were single and the sedimentation constants were around 3 S, suggesting that these sulfated glycopeptides were macromolecular components. Thus, the presence of highly sulfated glycoproteins was confirmed in chalazae and yolk membrane, which were different from those in ovomucin.  相似文献   

2.
The cellular distribution of arginyl-tRNA, leucyl-tRNA, methionyl-tRNA and phenylalanyl-tRNA synthetases from quiescent wheat germ shows that these enzymes participate to various high molecular weight complexes from 3.106 to 3.105. Two types of interactions were discriminated by salt washing. The greater part of these complexes are weakly bound and destroyed by conventional enzymatic extraction procedures which release the free enzymes. Sedimentation constants of complexes show that they have a common size at 18–20S, but higher sedimentation constants were also observed (? 40–60 S). Investigations by gel filtration lead to evidence that the complexes contain a little amount of conjugates.  相似文献   

3.
ABSTRACT

The complex nature of the antigens in suckling mouse-adapted MEFi virus was indicated by Selzer and Poison1, who found that the infectivity was associated with two components of approximate sedimentation coefficients 100 and 173 S respectively. In addition to these components a “soluble antigen” was found which had a sedimentation coefficient of about 22 S. These results, which were obtained by using a Spinco preparative centrifuge (Poison and Linder2), have now been confirmed in the Spinco analytical ultracentrifuge of the Nobel Institute, Stockholm, and other types of poliomyelitis virus have been studied in both instruments.  相似文献   

4.
A purification procedure for diol dehydrase (dl-1,2-propanediol hydro-lyase, EC 4.2.1.28) of Klebsiella pneumoniae (Aerobacter aerogenes) ATCC 8724 has been developed which gives the highest specific activity for this enzyme obtained so far. The purified enzyme is homogeneous by the criteria of ultracentrifugation (s20,w = 8.9 S) and disc gel electrophoresis in the presence of substrate. The molecular weight of approximately 230,000 was obtained by gel filtration and ultracentrifugal sedimentation equilibrium. The enzyme is composed of components F and S whose molecular weights were determined to be approximately 26,000 and 200,000, respectively, by gel filtration. The incubation of both components F and S with the substrate leads to complete reassociation of the components. Disc gel electrophoresis in the presence of sodium dodecyl sulfate and terminal amino acid analyses indicate that component S consists of at least four nonidentical subunits. The reversible association and heterogeneity of the subunits were also demonstrated with the crude enzyme by immunoelectrophoresis.  相似文献   

5.
  1. The egg white, thick and thin fractions, was solubilized in 1.0% SDS solution by vigorous mixing and subjected to gel filtration on a Sepharose 4B column, eluted with 1.0% SDS. The isolated thick and thin ovomucins were found by analytical disc electrophoresis to be free from contamination with lysozyme.

  2. In the velocity sedimentation the two ovomucin fractions behave similarly, both comprising at least two components with sedimentation coefficients 35 S and 30 S.

  3. The chemical compositions of the two ovomucin fractions showed only notable difference in that the carbohydrate content of the thick white ovomucin was somewhat higher than that of the thin white ovomucin. The amino acid profiles of the two fractions were similar.

  相似文献   

6.
Discrete RNA fractions sedimenting slightly slower than 18s ribosomal RNA have been found in mitochondrial preparations from both hamster (BHK-21) and mouse (L-929) cells. This RNA could be separated into two components, present in approximately equimolar amounts, by prolonged zonal centrifugation or acrylamide gel electrophoresis. The hamster components had sedimentation constants averaging 16.8 and 13.4, and molecular weights (estimated by gel electrophoresis) averaging 0.74 and 0.42 x 106 daltons. Mixed labeling experiments showed that the mouse components sedimented and electrophoresed 3–6% more slowly than the corresponding hamster components. The RNA from both cell lines resembled mitochondrial ribosomal RNA from yeast and Neurospora in being GC poor, and in addition the larger and smaller components resembled each other in base composition. These results, taken with those of other recent studies, are compatible with the idea that our high molecular weight mitochondrial RNA is ribosomal; such RNA would then constitute a uniquely small size-class of ribosomal RNA.  相似文献   

7.
Poly(A)-containing RNA isolated from the components of a HeLa cell mitochondrial lysate which sediment in the polysome region of a sucrose gradient have been analyzed for the presence of discrete species. Eight distinct components have been identified by polyacrylamide gel electrophoresis after formaldehyde treatment. These components, which are highly reproducible in their occurrence and relative amounts under widely varying conditions of isolation, have been characterized as to their sedimentation behavior under denaturing conditions, poly(A) content and homology to separated strands of mitochondrial DNA.One of the discrete components was previously shown to have a sedimentation coefficient of about 7 S in the native state and a molecular weight of about 9.0 × 104, as estimated from its sedimentation rate in formaldehyde. The molecular weights of the other seven components, as derived from sedimentation data, range between 2.6 and 5.3 × 105.The 7 S RNA is complementary to the light mitochondrial DNA strand, while the other seven components are complementary to the heavy strand. Together with the two mitochondrial rRNA species and with mitochondrial 4 S RNA, the eight poly(A)-containing RNA components, if distinct in sequence, would account for about 70% of the single-strand informational content of HeLa mitochondrial DNA.  相似文献   

8.
Arracacha virus A (AVA), a previously undescribed virus, is common in arracacha (Arracacia xanthorrhiza; Umbelliferae) in the Huanuco region of the Peruvian Andes. AVA was not transmitted by Myzus persicae, but was transmitted by inoculation of sap to 38 species from 10 families out of 63 species from 12 families tested. AVA was best propagated and assayed in Chenopodium quinoa and Nicotiana clevelandii in which it caused severe diseases. Sap from infected C. quinoa was occasionally infective after dilution to 10-4 but not 10-5, after 10 min at 65 °C but not 70 °C, and after 15 days at 20 °C. In neutral phosphotungstate, AVA has isometric particles c. 26 nm in diameter with a hexagonal profile, some of which were either fully or partially penetrated by the negative stain. Up to 50–200 E2601cm units of purified virus was obtained from 1 kg of infected N. clevelandii leaf by extraction in 0.05 M phosphate buffer at pH 7.5 containing 0.05 M ethylene diaminetetra-acetate, and clarification with chloroform, followed by differential precipitation with ammonium sulphate and three cycles of differential centrifugation. Purified virus sedimented as three components with sedimentation coefficients (S20w°) of 50 S, 92 S and 125 S and E260/E280 ratios of 0.65, 1.50 and 1.85 respectively. At equilibrium in CsCl gradients, buoyant densities of the 50, 92 and 125 S components were 1.32, 1.45 and 1.52 g/cm3 respectively. From the sedimentation coefficients and buoyant densities, the nucleic acid contents of the 92 S and 125 S components were estimated at 30–35% and 43–44% respectively. Only the 125 S component seemed to be infective but its infectivity was greater when mixed with the 92 S component. All three components contained a single protein with a molecular weight of 53 000. AVA was not serologically related to any of 33 other morphologically similar viruses. Although the vector is unknown, its properties suggest that it is a member of the nepovirus group. The cryptogram of AVA is */*: */43–44 +*/30–35: S/S:S/*.  相似文献   

9.
ABSTRACT

By using a reorienting gradient centrifuge rotor cut from a block of Nylon and fitted with eight septae, it was possible to separate the components of the haemolymph of the mollusc Turbo sarmaticus into three fractions in a sucrose gradient held in the bowl of the rotor. The fractions were (108 and 98)S, 44S and 16-22S. The success of the experiment was due to the large differences in the sedimentation coefficients of the components. When the rotor was applied to the natural mixture of the five viruses of the caterpillars of Nudaurelia cytheria only the main component could be isolated in a pure state. The viruses were separated by isopycnic centrifugation in “self formed” caesium chloride gradients, using a Beckman Model E analytical centrifuge in which a separation cell fitted with a centerpiece with two perforated partitions was used.

Centrifugation in gradients of inert substances is useful for the separation of components in a mixture1. There are two principles involved in this type of separation. One, termed reorienting gradient centrifugation (reograd) relies on the differences in masses or, better still on the sedimentation coefficients of the different components in the mixture and the second, termed isopycnic centrifugation2, on the densities or specific gravities of the different entities.  相似文献   

10.
U. Seitz  G. Richter 《Planta》1970,92(4):309-326
Summary By culturing of callus tissue originating from root explants of Petroselinum sativum in a synthetic liquid medium under aeration, freely suspended single cells and small clusters consisting of mostly five cells were obtained. The rapidly dividing cells did not exhibit any morphogenesis. Their nucleic acid metabolism was investigated by pulse experiments with 32P-orthophosphate. Rapidly labelled RNA was prominently found associated with high molecular RNA. During the fractionation of the total nucleic acids on MAK columns it was eluted after the ribosomal RNA components. Its base ratio, however, differed from the latter in that the AMP content was higher than the GMP content. Sucrose gradient centrifugation and polyacrylamide gel electrophoresis resulted in the separation of the ribosomal RNA from the rapidly labelled RNA, thus proving the higher molecular weight of the latter. Based upon the migration in the gel a sedimentation coefficient of approximately 32S was calculated. The possible function of the heavy rapidly labelled RNA component as precursor of ribosomal RNA is discussed.  相似文献   

11.
Cocoa necrosis virus (CNV) was transmitted by sap inoculation to twelve of twenty-one species tested. It was propagated and assayed in Phaseolus vulgaris. Sap from P. vulgaris was infective after dilution to 10-3but not 10-4, after 10 min at 60 d?C but not 65 d?C, and after 4 but not 7 days at 20–24 d?C. Lyophilized sap from P. vulgaris was infective after 2 years in vacuo. Virus was prepared by extracting infected leaves of P. vulgaris with 0.1 M phosphate (pH 7.5) containing 0.05 M ethylene diamine tetra-acetate and 0.02 M thioglycollate. After clarification with n-butanol, virus was purified by precipitation with polyethylene glycol and several cycles of differential centrifugation. Such preparations were very infective and contained numerous particles, 24–26 nm in diameter with a hexagonal profile, which sedimented as two components with sedimentation coefficients (Sd?20,w) of 101 S and 129 S. The absorption spectra of both components with maximum and minimum absorption at 259 and 240 nm respectively were typical of nucleoproteins (101 S component, A 260/280 = 1.63; A 260/240 = 1.40:129 S component, A260/280 = 1.78; A260/240 = 1.58) and indicated nucleic acid contents of ca. 35% for the 129 S component and ca. 20% for the 101 S component; values calculated from the sedimentation coefficients were 41 and 30% respectively. Only the 129 S component seemed to be infective and was not more so when mixed with 101 S component. Both components contained a single protein subunit weighing ca. 60000 daltons. Under certain conditions sap fractionated without butanol gave virus preparations containing empty protein shells (54 S) and small spherical particles (20–30 S) ca. 12 nm diameter. CNV is a serotype of tomato blackring virus and is distantly related to Hungarian chrome mosaic virus. The cryptogram of CNV is */*:*/(35–41):S/S:S/*.  相似文献   

12.
R5020(17,21-dimethyl-19-nor-4,9-pregnadiene-3,20-dlone)-binding components with sedimentation coefficient of 8S were detected in sexual skin cytosols from estrogen-primed ovarlectomized Japanese monkey (Macaca fuscata fuscata). In contrast, little 8S binding was found In similar preparations from the abdominal skin. The dissociation constants and the number of binding sites of the components were l.6×10?10M and 36 fmoles/mg cytosol protein, respectively. The 8S binding components were specific for progestational compounds. Incubation with pronase abolished the 8S binding. Thermal experiments revealed the thermolabile nature of the components. Moreover, the concentration of the R5020-binding components was markedly increased by estradiol-17β 3-benzoate injections. We conclude from these results that the cytosols from the sexual skin of estrogen-primed female monkeys contain progesterone receptors.  相似文献   

13.
The energy transducing adenosine 5′-triphosphatase (ATPase) complex was extracted with deoxycholate from Escherichia coli membranes and purified 20–25 fold. The detergent-solubilized ATPase complex was inhibited more than 80% by dicyclohexylcarbodiimide (DCCD). Its sedimentation velocity coefficient was 14.7s in the presence of deoxycholate. Phospholipid stimulated its hydrolytic activity and maximized DCCD sensitivity. These parameters clearly differentiate the ATPase complex from the DCCD-insensitive, soluble ATPase prepared by extraction with EDTA at low ionic strength. The purified ATPase complex showed twelve discrete bands on lauryl sulfate gel electrophoresis. Five of these components co-electrophresed with subunits of soluble ATPase. Of the seven additional components, primarily two were precipitated with antibody to soluble ATPase. The protein which specifically reacts with DCCD co-migrated with one of these subunits.  相似文献   

14.
A chitooligosaccharide specific lectin (Luffa acutangula agglutinin) has been purified from the exudate of ridge gourd fruits by affinity chromatography on soybean agglutinin-glycopeptides coupled to Sepharose-6B. The affinity purified lectin was found homogeneous by polyacrylamide gel electrophoresis, in sodium dodecyl sulphate-polyacrylamide gels, by gel filtration on Sephadex G-100 and by sedimentation velocity experiments. The relative molecular weight of this lectin is determined to be 48,000 ±1,000 by gel chromatography and sedimentation equilibrium experiments. The sedimentation coefficient (S20, w) was obtained to be 4.06 S. The Stokes’ radius of the protein was found to be 2.9 nm by gel filtration. In sodium dodecyl sulphate-polyacrylamide gel electrophoresis the lectin gave a molecular weight of 24,000 in the presence as well as absence of 2-mercaptoethanol. The subunits in this dimeric lectin are therefore held by non-covalent interactions alone. The lectin is not a glycoprotein and circular dichroism spectral studies indicate that this lectin has 31% α-helix and no β-sheet. The lectin is found to bind specifically to chitooligosaccharides and the affinity of the lectin increases with increasing oligosaccharide chain length as monitored by near ultra-violet-circular dichroism and intrinsic fluorescence titration. The values of ΔG, ΔH and ΔS for the binding process showed a pronounced dependence on the size of the oligosaccharide. The values for both ΔH and ΔS show a significant increase with increase in the oligosaccharide chain length showing that the binding of higher oligomers is progressively more favoured thermodynamically than chitobiose itself. The thermodynamic data is consistent with an extended binding site in the lectin which accommodates a tetrasaccharide. Based on the thermodynamic data, blue shifts and fluorescence enhancement, spatial orientation of chitooligosaccharides in the combining site of the lectin is assigned.  相似文献   

15.
Changes in the proteins of chickpea during a 12-day germination period are reported using techniques of gel filtration, DEAE-cellulose chromatography, polyacrylamide gel (PAG) electrophoresis and ultracentrifugation. In the ultracentrifuge, the total proteins of dormant seeds resolve into 3 components which have the sedimentation coefficients of 2.2 S, 6.9 S and 10.3 S respectively. On germination, the presence of fractions of lower sedimentation coefficient indicates possible degradation of these components; in the early stages, the degradation rate of the 7 S fraction is higher, while the 10 S fraction is broken down faster in the later stages. Gel filtration experiments indicate the possibility of degradation of high polymer into intermediary products. Increase in the relative mobility of protein components on PAG and elution constant on DEAE-cellulose chromatographs indicates an increase in the net negative charge of the protein fractions. The accumulation of subunits of the proteins is negligible during the germination period.  相似文献   

16.
Porcine myoglobin was isolated by fractionation with ammonium sulfate and crystallized with 3.8 M phosphate buffer.

Chromatography of the porcine crystalline myoglobin on a molecular-sieve column gave a single elution band, which agreed well with that of horse myoglobin.

By ultracentrifugal analysis, the sedimentation constant (s20,w), was found to be 1.96 S.

The iron content of the myoglobin was 0.324%. This value corresponds to the minimal molecular weight of 17,200.

Absorption curves and millimolar extinction coefficients of the porcine myoglobin in several derivatives, namely, reduced (RMb), met (MMb), carboxy (MbCO) and cyanment (MMbCN) forms were examined in the visible region. The spectral characteristics of the porcine myoglobin derivatives were in good agreement with those of horse myoglobin,

Three components were detected for the porcine myoglobin by starch gel electrophoresis, and each of them had higher migration velocity than those of horse myoglobin.  相似文献   

17.
Total HMW-RNAs were prepared by three different methods (method with phenol, method with NaClO4, method without phenol using Ultrogel AcA 22 filtration). Giant RNAs were obtained in the void volume by filtration on Sepharose 2B. The giant RNAs/total HMW-RNA ratio is higher (6.77%) with the gel filtration method than with phenol or NaClO4 methods (1.41% and 1.00% respectively). The nucleotide composition of these RNAs is DNA-like and the sedimentation constants are approximately 70-100 S.  相似文献   

18.
It was shown by autoradiography in previous papers that RNA which is synthesized before mitosis and located in the nuclei, enters the cytoplasm at the onset of mitosis and returns to the nuclei of the daughter cells after mitosis. In order to study thenature of this migrating RNA we performed a sedimentation analysis of RNA isolated from the cytoplasm and chromosomes (nuclei) of metaphase and interphase cells in the synchronized culture of the Chinese hamster. Whereas the cytoplasm of interphase cells is found to contain RNA with sedimentation constants not higher than 28S, the cytoplasm of metaphase cells includes precursors of ribosomal and messenger RNA with sedimentation constants 32S, 45S and even higher. This means that RNA migrating from nuclei to cytoplasm during cell division retains its nuclear character. It is suggested that this property provides for the return of RNA synthesized before mitosis to the nuclei of the daughter cells.  相似文献   

19.
Protein(s) have been found in a wide range of tissues which have a high affinity for 25-hydroxycholecalciferol. Of the tissues examined only erythrocytes do not have this protein. The properties of the protein have been examined and it has been found that the association constants range from 2 · 109 to 5 · 109 M−1 and the sedimentation constants between 5.0 and 6.0 S. It was not possible to distinguish the proteins from the different tissues by their S values, mobility on gel electrophoresis or behaviour on ion-exchange chromatography. These techniques were all used, however, to show that the tissue 25-hydroxycholecalciferol binding protein is distinct from the main plasma binding protein for this steroid and from the intestinal 1,25-dihydroxycholecalciferol-binding protein. A protein has been found in the plasma of rachitic animals but not of normals, which is apparently indistinguishable from this new tissue 25-hydroxycholecalciferol-binding protein. The steroid specificity of this new binding protein has been shown to be dependent upon a C-25 hydroxyl group, and an intact conjugated double bond system. Possible functions for this protein have been briefly discussed.  相似文献   

20.
Sedimentation coefficients and apparent molecular masses of 5.8S rRNA from rat liver and yeast (Saccharomyces cerevisiae) depend considerably on the ionic strength and the kind of ions in solution. At 20°C the sedimentation coefficient of 5.8S rRNA in 10 mm sodium cacodylate, pH 7.0, amounts to 5.1 ± 0.2 S. By addition of NaCl up to 1.1 m the data increase reversibly to 6.1 ± 0.2 S (rat liver) or 5.4 ± 0.1 S (yeast) without significant changes of the molar mass (52 000 ± 2000) g/mol. Similar effects but with different extent were obtained using KCl or LiCl. These results can be explained by counterion effects on the conformation and changing of the water shell surrounding the RNA molecule. Short heat incubation (5 min at 65°C) and immediate cooling of rat liver 5.8S rRNA lead to dimer or oligomer formation. Its portions depend strongly on RNA concentration and are enhanced also with increasing NaCl concentration and incubation temperature as can be seen fro higher sedimentation coefficients and molecular masses as well as from additional bands in the electrophoretic pattern. At 20°C MgCl2 provokes, in concentrations up to 1.5 mm, a reversible increase of sedimentation coefficients of rat liver 5.8S rRNA to 6.65 ± 0.1 S whereas the molecular mass remains unchanged indicating strong Mg++ effects on conformation and/or water shell of the 5.8S rRNA. A further increase of sedimentation coefficients up to 8.2 ± 0.1 S combined with higher apparent molar masses up to 90 000 g/mol was observed in the presence of 30 to 50 mm MgCl2. In this concentration range of Mg++ the association constants of 5.8S rRNA dimerization increase from about 105to 3 × 107m?1. After removal of free Mg++ by addition of EDTA the 5.8S rRNA dimers dissociate if no incubation step at higher temperature in involved. The Mg++ induced 5.8S rRNA dimers differ in their stability from those formed by incubation at 65°C in the presence of higher concentrations of monovalent ions.  相似文献   

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