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1.
A low molecular weight immunosuppressive factor FA which is able to reduce the blastic transformation capacity of lymphoid cells from treated mice has been characterized. It was prepared from a bovine spleen acetone powder and found to be associated partly with high molecular weight carriers in the form of an active complex characterized previously as part of a ‘lymphoid chalone’ fraction. FA may be obtained by selective ultrafiltration of F followed by P-2 Biogel chromatography of the ultrafiltrate. Thymidine, deoxyinosine and deoxycytidine have been identified as the major constituents of FA by mass spectrometry, ultraviolet absorption data and thin layer chromatography. However, none of these nucleotides has the biological activity of FA.  相似文献   

2.
Three enzymes possessing RNAase activity were isolated from barley seeds. These enzymes were further purified by ammonium sulphate precipitation DEAE-cellulose chromatography, gel filtration on Sephadex G-75 and DEAE-Sephadex A-50 chromatography. These enzymes have been characterized and classified as: 1. Plant RNAase I (EC 3.1.27.1). It has a pH optimum at 5.7 and molecular weight of 19 000. 2. Plant RNAase II (EC 3.1.27.1). It has a pH optimum at 6.35 and molecular weight of 19 000. 3. Plant nuclease I (EC 3.1.30.2). It has a pH optimum at 6.8 and molecular weight of 37 000. Two RNAases were purified to homogeneity by means of affinity chromatography on poly(G)-Sepharose 4B, as shown by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.  相似文献   

3.
Fragment D has been isolated as an apparently single molecular weight species (molecular weight about 100,000) from plasmin digests of humman fibrinogen, using a combination of affinity chromatography on insolubilized "fibrin monomer" and gel filtration. This fragment consists of three chains with molecular weights of 15,000 (Dbeta), 42,500 (Dgamma1) or 39,500 (Dgamma2), and 14,000 (Dalpha) held together by disulfide bonds. The S-carboxymethyl derivatives of the chains have been separated by gel filtration and ion exchange chromatography, and their identity has been confirmed by peptide mapping and immunological analysis. The chain with a molecular weight of 45,000 is a fragment of the Bbeta chain of fibrinogen. The chain derived from the gamma chain of fibrinogen occurred in two molecular forms having molecular weight 42,500 and 39,500. The chain derivative with molecular weight 14,000 is most likely derived from the Aalpha chain of fibrinogen. The chains were characterized by NH2-terminal sequence analysis, amino acid composition, and carbohydrate staining. The two molecular analysis, amino acid composition, and carbohydrate staining. The two molecular forms of the gamma chain appeared to be identical except for an NH2-terminal peptide extension of 23 amino acid residues in the longer chain. The latter has sequences in common with the COOH-terminal part of the gamma chain of the NH2-terminal disulfide knot (BROMBACK, B., BRONDAHL, N. J., HESSEL, B., IWANAGA, S., and WALLEN, P. (1973) J. Biol. Chem. 248, 5806-5820); its NH2-terminal residue being Ala-63 of the gamma chain of fibrinogen.  相似文献   

4.
Carrier-free 203Pb has been used to label high affinity lead-binding proteins in rat brain cytosol to allow their initial characterization. The low molecular weight 203Pb-protein complex collected from a Sephadex G-75 column eluate has been further purified by Sephadex DEAE chromatography and then partially characterized. The protein has a molecular weight of 23,000 daltons as determined by SDS polyacrylamide gel electrophoresis and significant levels of glutamic acid (9.3%), aspartic acid (10.8%) and cysteine (9.4%). Western blot studies conducted using the polyclonal antibody to the renal lead-binding proteins showed a lack of reactivity, indicating that the brain protein is immunologically distinct from that found in the kidney.  相似文献   

5.
Rat liver alcohol dehydrogenase. Purification and properties   总被引:3,自引:2,他引:1       下载免费PDF全文
Alcohol dehydrogenase (EC 1.1.1.1) from the rat liver supernatant fraction has been purified 200-fold and partially characterized. The isolation procedure involved ammonium sulphate fractionation, DEAE-Sephadex chromatography and gel filtration. The purified enzyme behaved as a homogeneous preparation as evaluated by cellulose acetate and polyacrylamide-gel disc electrophoresis. Sulphoethyl-Sephadex chromatography and immunoelectrophoresis with rabbit antiserum indicated the presence of a minor component. Rat liver alcohol dehydrogenase appears to contain 4mol of zinc/mol, has an estimated molecular weight of 65000 and consists of two subunits of similar molecular weight. Heavy-metal ions, thiol-blocking reagents, urea at concentrations below 8m, low pH (5.5) and chelating agents deactivate the enzyme but do not dissociate it into subunits. Deactivated enzyme could not be reactivated. The enzyme is strictly specific for NAD(+) and has a broad specificity for alcohols, which are bound at a hydrophobic site. Inhibition occurred with the enzyme equilibrated with Zn(2+) at concentrations above 0.1mm.  相似文献   

6.
We isolated the feather-degrading Bacillus pseudofirmus FA30-01 from the soil sample of poultry farm. The isolate completely degraded feather pieces after liquid culture at 30°C (pH 10.5) for 3 days. Strain FA30-01 is a Gram-positive, spore-forming, rod-shaped bacterium and was identified with B. pseudofirmus based on 16S rDNA analysis. The keratinase enzyme produced by strain FA30-01 was refined using ammonium sulfate precipitation, negative-ion DEAE Toyopearl exchange chromatography, and hydroxyapatite chromatography. The refinement level was 14.5-fold. The molecular weight of this enzyme was 27.5 kDa and it had an isoelectric point of 5.9. The enzyme exhibited activity at pH 5.1–11.5 and 30–80°C with azokeratin as a substrate, although the optimum pH and temperature for keratinase activity were pH 8.8–10.3 and 60°C, respectively. This enzyme is one of the serine-type proteases. Subtilisin ALP I and this enzyme had 90% homology in the N-terminal amino acid sequence. Since this enzyme differed from ALP I in molecular weight, heat resistance and isoelectric point, they are suggested to be different enzymes.  相似文献   

7.
SELECTIVE RETENTION AND FILTRATION OF BRAIN NUCLEIC ACIDS IN AGAROSE GELS   总被引:2,自引:1,他引:1  
Abstract— Total nucleic acids of rat brain have been separated by agarose gel chromatography at 2 m -NaCl into DNA. transfer RNA plus low molecular weight RNA. and high molecular weight RNA fractions. The DNA fraction contained less than 1 per cent RNA by weight judged by either short-term or long-term labelling with ortho[32P]phosphate. The high molecular weight RNA fraction contained 28 s and 18 s ribosomal RNAs and a heterogeneous population of 20-60 s RNAs, apparent after short-term labelling and characterized by a high content of nearest-neighbour-labelled uridylic acid. The rapidly sedimenting (>30 s ) portion of these RNAs could be largely separated from ribosomal RNAs by gel filtration using 4% agarose. The ribosomal RNAs could be fully resolved into 28 s and 18 s components by agarose gel chromatography at 0.5 m -0.6 m -NaCl, as shown by analysis of their sedimentation and nucleotide composition.  相似文献   

8.
In this research, protease enzyme was purified and characterized from milk of Euphorbia amygdaloides. (NH4)2SO4 fractionation and CM-cellulose ion exchange chromatography methods were used for purification of the enzyme. The optimum pH value was determined to be 5, and the optimum temperature was determined to be 60 degrees C. The V(max) and K(M) values at optimum pH and 25 degrees C were calculated by means of Linewearver-Burk graphs as 0.27 mg/L min(-1) and 16 mM, respectively. The purification degree was controlled by using SDS-PAGE and molecular weight was found to be 26 kD. The molecular weight of the enzyme was determined as 54 kD by gel filtration chromatography. These results show that the enzyme has two subunits.In the study, it was also researched whether purified and characterized protease can be collapsed to milk. It was determined that protease enzyme can collapse milk and it can be used to produce cheese.  相似文献   

9.
Low molecular weight proteins co-purified with IgG constitute 0.22% of the total protein purified from human plasma by ion-exchange chromatography on DEAE-cellulose. We have found that these low molecular weight proteins were obtained free of immunoglobulin by ultrafiltration in 5 M guanidinium chloride. Electrophoresis and isoelectric focusing in polyacrylamide gels demonstrated that this fraction of low molecular weight proteins is remarkably heterogeneous. Chromatography of an Mr 6000 to 12 000 fraction on hydroxyapatite resolved fourteen discrete protein peaks. Three of the peaks contained proteins which appeared to be homogeneous on acid-urea polyacrylamide gels. Two of these proteins were similar in composition to B2 globulin and may represent degradation products of some larger protein. The third protein was found to have an amino-terminal sequence identical to C3a. This population of low molecular weight plasma proteins has previously been shown to contain the cystic fibrosis mucociliary inhibitor and is here shown to contain two proteins similar to B2 globulin, C3a and many proteins remaining to be characterized. The presence of these low molecular weight proteins in measurable concentrations may be insufficiently appreciated in studies using 'purified' immunoglobulins as biological or chemical probes.  相似文献   

10.
Fanconi anemia (FA) is a rare hereditary disorder characterized by skeletal abnormalities, bone marrow failure, and an increased incidence of cancer. The basic cellular abnormality in FA has been postulated to lie in the DNA repair mechanisms because cells from FA patients display chromosomal breakage, which is particularly remarkable following induction of DNA crosslinks. However, experimental evidence for this hypothesis has been lacking. To test whether DNA repair is really defective in FA cells, we disrupted several FA genes in chicken B cell line DT40. By measuring efficiency of gene conversion and hypermutation at the Immunoglobulin locus, we have shown that DT40 FA mutant cell lines exhibited defects in homologous DNA recombination, and possibly, translesion synthesis. However, levels of sister chromatid exchange, another important cellular event mediated by HR, were not reduced, possibly indicating the role of FA genes only in a subpathway of HR. Our results indicate that chicken DT40 cells could be highly useful in molecular dissection of basic biochemical processes, which are deficient in a human genetic disorder.  相似文献   

11.
Alkaline phosphatase of cultured rat ascites hepatoma cells has been purified by butanol extraction, DEAE-cellulose column chromatography, gel filtration through Sephadex G-200, concanavalin A-Sepharose affinity chromatography, and polyacrylamide gel electrophoresis. Affinity chromatography confirmed the glycoprotein nature of alkaline phosphatase from cultured rat ascites hepatoma cells. Electrophoresis on polyacrylamide gels of various concentrations indicated a molecular weight of 290,000. The molecular weight of the subunit was estimated to be 72,000 by SDS-polyacrylamide gel electrophoresis. These findings suggest that alkaline phosphatase of cultured rat ascites hepatoma cells is a tetramer with a subunit molecular weight of 72,000.  相似文献   

12.
Rhodanese (thiosulphate sulphurtransferase , EC 2.8.1.1.) from Cercopithecus aethiops (vervet monkey) liver has been isolated and purified by means of extraction, ammoniumsulphate and pH fractionation, anion-exchange chromatography, Sephacryl S-300 gel chromatography and cation-exchange chromatography. A yield of about 10% pure enzyme with a specific activity of 242 U/mg protein corresponding to a purification factor of 523 was obtained. The enzyme was physically characterized and its homogeneity determined by electrophoretic studies and gel chromatography. The rhodanese enzyme has a molecular weight of 37,000 daltons, a D020 ,w value of 7.6 X 10(-7) cm2 sec-1, a Stokes radius (molecular size) of 2.75 X 10(-7) cm and a frictional ratio of 1.071.  相似文献   

13.
An aggregation factor (AF) from the siliceous sponge Suberites domuncula has been isolated and purified by the following steps: Sepharose 2 B gel chromatography, sucrose gradient, Nonidet treatment, Sephadex G-100 gel chromatography and DEAE-Sephadex ion-exchange chromatography. By this procedure the AF was purified 1340-fold with a 63% yield nearly to homogeneity. The AF is originally associated with large particles, characterized by a sedimentation of 2200 S. These particles have been visualized electron microscopically; they are characterized by a filament-like shape of a length of 3400 Å and a cross-sectional diameter of 230 Å.
The purified, low-molecular weight AF has a buoyant density of 1.38 g/cm3 and an absorbance maximum at 282 nm. The isoelectric pH is approximately 5.75. The molecular weight of the AF has been determined to be 55,000. Chemical analysis revealed that AF consists mainly of protein.
The reaggregation process of Suberites cells to large aggregates (>1000 μm), mediated by Suberites AF, is strongly dependent on pH, ionic strength and the presence of calcium ions, and independent of incubation temperature between 0°C and 20°C. Aggregation can be inhibited by trypsin, D-glucosamine and dodecyl sulphate.
The Suberites AF is species-specific if tested in a system containing cells from the siliceous sponge Geodia cydonium .  相似文献   

14.
The heat-stable, protein inhibitor of the cyclic adenosine monophosphate (cAMP) dependent protein kinase [Walsh, D. A., Ashby, C. D., Gonzalez, C., Calkins, D., Fischer, E., & Krebs, E (1971a) J. Biol. Chem. 246, 1977-1985] has been purified to homogeneity from rabbit skeletal muscle by preparative electrophoresis. Employing a more sensitive assay system, we detected multiple charged forms of the inhibitor on diethylaminoethyl chromatography; the form that has been further characterized is the predominant species in skeletal muscle comprising greater than 70% of the total. The apparent molecular weight of the protein inhibitor, as determined by Sephadex G-75 gel exclusion chromatography, is 22 000 in initial cellular extracts and at all stages during the purification prior to the final purification step of preparative gel electrophoresis, after which the homogeneous protein exhibits a molecular weight of 11 000. These two forms are designated I and I', respectively. The I form migrates with an apparent molecular weight of 10 000 on nondenaturing gel electrophoresis and of 10 500-11 500 on sodium dodecyl sulfate (NaDodSO4) gel electrophoresis; the I' form migrates with an apparent molecular weight of 6500-8300 on NaDodSO4 electrophoresis and has a minimum molecular weight of 10 400 by amino acid analysis. Taking into account the anomalous behavior displayed by low molecular weight proteins with the various techniques employed, we suggest that the I and I' forms of the protein inhibitor may represent shape conformers.  相似文献   

15.
A high molecular weight glycoprotein found associated with a nuclear matrix-pore complex-lamina (NMPCL) preparation obtained from Drosophila melanogaster embryos has been shown by in vitro analyses to be largely confined to this subcellular fraction. In contrast with several of the NMPCL proteins, this glycoprotein remains completely insoluble after treatment with 5 M urea. It has, therefore, been possible to separate the glycoprotein from other NMPCL components by differential urea extraction. The glycoprotein in the 5 M urea-extracted pellet has been solubilized by boiling in sodium dodecyl sulfate and purified to near-homogeneity by sequential steps of chromatography on hydroxylapatite and Sephacryl S-300 (both run in the presence of 0.1% sodium dodecyl sulfate), followed by affinity chromatography on lentil lectin-Sepharose. Over 30 hybridoma cell lines producing antibodies against this glycoprotein have been obtained. Monoclonality has been established for two of these lines (designated AGP-26 and AGP-78), and the antibodies they secrete have been further characterized. Western blot analysis has shown both antibodies to be monospecific (with respect to other Drosophila embryo polypeptides) for the major NMPCL glycoprotein; in addition, antibody AGP-78 has been shown to be weakly cross-reactive with glycoproteins of similar or identical molecular weight found associated with isolated nuclear fractions obtained from Xenopus oocytes, as well as chicken, opossum, and rat livers. Finally, both antibodies AGP-26 and AGP-78 react exclusively with the Drosophila nuclear periphery (nuclear envelope) in situ as demonstrated by indirect immunofluorescence analysis of larval cryosections. Based on these results as well as upon those of biochemical studies reported previously (Berrios, M., Filson, A. J., Blobel, G, and Fisher, P. A. (1983) J. Biol. Chem. 258, 13384-13390), we conclude that the major Drosophila NMPCL glycoprotein is the specific homolog of the high molecular weight glycoprotein recently shown using immunoelectron microscopy to be a distinct component of the rat liver nuclear pore complex (Gerace, L., Ottaviano, Y., and Kondor-Koch, C. (1982) J. Cell Biol. 95, 826-837).  相似文献   

16.
Dietary ferulic acid (FA), a significant antioxidant substance, is currently the subject of extensive research. FA in cereals exists mainly as feruloylated sugar ester. To release FA from food matrices, it is necessary to cleave ester cross-linking by feruloyl esterase (FAE) (hydroxycinnamoyl esterase; EC 3.1.1.73). In the present study, the FAE from a human typical intestinal bacterium, Lactobacillus acidophilus, was isolated, purified, and characterized for the first time. The enzyme was purified in successive steps including hydrophobic interaction chromatography and anion-exchange chromatography. The purified FAE appeared as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 36 kDa. It has optimum pH and temperature characteristics (5.6 and 37 degrees C, respectively). The metal ions Cu(2+) and Fe(3+) (at a concentration of 5 mmol liter(-1)) inhibited FAE activity by 97.25 and 94.80%, respectively. Under optimum pH and temperature with 5-O-feruloyl-L-arabinofuranose (FAA) as a substrate, the enzyme exhibited a K(m) of 0.0953 mmol liter(-1) and a V(max) of 86.27 mmol liter(-1) min(-1) mg(-1) of protein. Furthermore, the N-terminal amino acid sequence of the purified FAE was found to be A R V E K P R K V I L V G D G A V G S T. The FAE released FA from O-(5-O-feruloyl-alpha-L-arabinofuranosyl)-(1-->3)-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose (FAXX) and FAA obtained from refined corn bran. Moreover, it released two times more FA from FAXX in the presence of added xylanase.  相似文献   

17.
It has been demonstrated that the composition of molecular species of adipose tissue triacylglycerols (TGs) from farm animals are not equally synthesized and that some molecular species are preferentially synthesized. The objective of the present study was to determine whether exogenous fatty acids (FAs) would affect the TG composition. To this end, the composition of TG molecular species stored in porcine adipocytes differentiated with several long-chain FAs was analyzed by gas chromatography. The addition of each FA for 6 d increased TG molecular species having two or three added FAs. However, the molecular species compositions at 15 d after the addition of each FA resembled those of cells with no added FAs. Moreover, some common molecular species in all experimental cells increased, as well as cells with no added FAs. It was concluded that the addition of FAs increases the contents of specific molecular species, but does not affect the synthetic processes of individual TG molecular species.  相似文献   

18.
It has been demonstrated that the composition of molecular species of adipose tissue triacylglycerols (TGs) from farm animals are not equally synthesized and that some molecular species are preferentially synthesized. The objective of the present study was to determine whether exogenous fatty acids (FAs) would affect the TG composition. To this end, the composition of TG molecular species stored in porcine adipocytes differentiated with several long-chain FAs was analyzed by gas chromatography. The addition of each FA for 6 d increased TG molecular species having two or three added FAs. However, the molecular species compositions at 15 d after the addition of each FA resembled those of cells with no added FAs. Moreover, some common molecular species in all experimental cells increased, as well as cells with no added FAs. It was concluded that the addition of FAs increases the contents of specific molecular species, but does not affect the synthetic processes of individual TG molecular species.  相似文献   

19.
Growth factor activity has been identified in the chondrocytes and extracellular matrix (ECM) fractions of human costal cartilage. There was about five times more growth factor activity in the ECM than was found to be associated with the chondrocytes. The growth factor activity in chondrocytes was found to be associated with chromatin. Both the chromatin-associated growth factor (CAGF) activity and extracellular matrix growth factor (EMGF) activity were characterized for molecular weight, charge, and the effect of reduction by sulfhydryl reducing reagents. Biorex cation exchange chromatography showed that both CAGF and EMGF were cationic. CAGF and EMGF have molecular weights between 15,000 and 18,000 as determined by size exclusion chromatography on HPLC TSK 3000 columns equilibrated with guanidine-HCl and dithiothreitol.  相似文献   

20.
The low molecular weight proteins of rat apo HDL and apo VLDL have been isolated and analyzed by the technique of isoelectric focusing. Sephadex fractions from apo HDL (HS-3) and apo VLDL (VS-3) that contain these proteins reveal three major bands with apparent isoelectric points of pH 4.50, 4.67, and 4.74, as well as three minor bands at pH 4.43, 4.57, and 4.61. In addition, apo HDL has a major band at pI of 4.83. DEAE-Cellulose chromatography was used to prepare purified fractions of these components that were characterized by N-terminal analyses and molecular weight determinantions by SDS gel electrophoresis. The major low molecular weight components of apo HDL were focused on a slab gel and the bands were identified as A-II (pI 4.83), C-II (pI 4.74), C-III-0 (pI 4.67), and C-III-3 (pI 4.50). Neuraminidase treatment of apo HDL, followed by isoelectric focusing, suggested that the other bands, which have not previously been reported, may be additional forms of the C-III protein, differing only in their content of sialic acid.  相似文献   

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