首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The complete amino acid sequence of a lactose-bindingCytisus sessilifolius anti-H(O) lectin II (CSA-II) was determined using a protein sequencer. After digestion of CSA-II with endoproteinase Lys-C or Asp-N, the resulting peptides were purified by reversed-phase high performance liquid chromatography (HPLC) and then subjected to sequence analysis. Comparison of the complete amino acid sequence of CSA-II with the sequences of other leguminous seed lectins revealed regions of extensive homology. The amino acid sequence of a putative carbohydrate-binding domain of CSA-II was found to be similar to those of several anti-H(O) leguminous lectins, especially to that of thel-fucose-bindingUlex europaeus lectin I (UEA-I).Abbreviations BPA Bauhinia purpurea lectin - Con A concanavalin A - CMA-I Cytisus multiflorus lectin I - CMA-II Cytisus multiflorus lectin II - CSA-I Cytisus sessilifolius lectin I - CSA-II Cytisus sessilifolius lectin II - CSII Cytisus scoparius lectin II - ECorL Erythrina corallodendron lectin - GSIV Griffonia simplicifolia lectin IV - HPLC high performance liquid chromatography - LAA-I Laburnum alpinum lectin I - LAA-II Laburnum alpinum lectin II - LOL Lathyrus ochrus lectin - LTA Lotus tetragonolobus lectin - MAH Maackia amurensis haemagglutinin - PSA Pisum sativum lectin - SDS sodium dodecyl sulfate - TFA trifluoroacetic acid - UEA-I Ulex europaeus lectin I - UEA-II Ulex europaeus lectin II - VFA Vicia faba lectin  相似文献   

2.
Two major lectins (lectin I and lectin II) were purified to homogeneity from the seeds of Araucaria brasiliensis (Gymnospermae). The purity of the lectins was confirmed by polyacrylamide gel electrophoresis, isoelectric focusing, and high performance liquid chromatography. They are glycoproteins in nature containing 6.3 and 2.9%, respectively, of neutral sugar and have absorption coefficients of 3.8 and 4.7, respectively, at 280 nanometers. The molecular weights of both lectins obtained by gel filtration on Sephacryl S-400 were equal: 200,000. After dissociation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, molecular weights were 20,000 and 34,000, respectively, for lectin I and lectin II, suggesting they are decameric and hexameric in nature. The amino acid composition of both lectins showed little difference, but both had high amounts of acidic amino acids and lacked methionine in their molecule. The carbohydrate binding specificity of lectins was directed towards mannose, glucose, and their oligomers. High inhibitory activity was also found with thyroglobulin. The erythroagglutinating activity of the lectins was enhanced in the presence of high-molecular-weight substances both at 37 and 4°C. Divalent cations do not appear to be essential for activity. They maintained their agglutinating activity over a broad but different range of pH: 5.5 to 7.5 and 6.5 to 7.5, respectively. Both lectins agglutinated erythrocytes of human ABO blood types equally well.  相似文献   

3.
Peptide fragments have been obtained from L-fucose-binding anti-H(O) lectins [Lotus tetragonolobus lectin (LTA) and Ulex europeus lectin I (UEA-I)] and di-N-acetylchitobiose-binding anti-H(O) lectins [Ulex europeus lectin II (UEA-II) and Laburnum alpinum lectin I (LAA-I)] by treatment with endoproteinase Asp-N or Lys-C. The peptide fragments were fractionated by affinity chromatography on a column of Fuc-Gel for LTA and UEA-I, and on a column of N-acetyl-D-glucosamine oligomer-Sepharose for UEA-II and LAA-I. The peptides with affinity for these columns were identified by peptide sequencing. All of these retarded peptides were found to be parts of the metal-binding regions of these lectins. It is strongly suggested that these peptides represent the carbohydrate-binding and metal ion-binding sites of legume lectins, respectively.  相似文献   

4.
The primary structures of two types of the Ulex europeus seed lectin   总被引:2,自引:0,他引:2  
The complete amino acid sequences of the Ulex europeus anti-H(O) lectins I and II were determined by using a protein sequencer. After digestion with endoproteinases Lys-C and Asp-N of the lectins reduced with 2-mercaptoethanol and modified with iodoacetamide, the resulting peptides were purified by reversed-phase high-performance liquid chromatography and subjected to sequence analysis. The complete primary structures of these two Ulex lectins I and II were compared with those of nine lectins already determined, including that of Lotus tetragonolobus anti-H(O) lectin which we have determined. Extensive homologies were found among them.  相似文献   

5.
Lectins were isolated from fruits and leaves of Clerodendron trichotomum by affinity chromatography on lactamyl-Sepharose. The purified lectins (C. trichotomum agglutinin: CTA) were homogeneous on SDS/polyacrylamide gel electrophoresis, and the carbohydrate moiety was characterized by physicochemical and immunochemical methods. The asparagine-linked oligosaccharides were released by treatment with N-oligosaccharide glycopeptidase (almond, EC 3.5.1.52) of peptic glycopeptides obtained from fruit CTA, and separated by gel filtration and thin-layer chromatography. The structure of the predominant oligosaccharide was determined as Xyl beta 1----2 (Man alpha 1----6)(Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4(Fuc alpha 1----3)GlcNAc by high-performance liquid chromatography, sugar analysis and 1H-NMR spectroscopy. The reactivity of the carbohydrate moiety of CTA toward various lectins was studied. Fruit and leaf CTAs were applied to polyacrylamide gel electrophoresis, transferred to nitrocellulose sheets and detected with horseradish-peroxidase-conjugated lectins. Concanavalin A, lentil lectin, pea lectin, Vicia faba lectin and Ulex europeus agglutinin I, but not wheat germ lectin, bound to fruit CTA. The results indicate new binding properties of these plant lectins: a beta-xylosyl residue substituted at C-2 of the beta-mannosyl residue of N-linked oligosaccharide does not affect the binding with mannose-specific lectins, lentil, pea and Vicia faba lectins can bind to N-linked oligosaccharides containing an alpha-L-fucosyl residue attached to C-3 of the asparagine-linked N-acetyl-D-glucosamine residue, and Ulex europeus agglutinin I can bind to the (alpha 1----3)-linked fucose residue of the N-linked oligosaccharide.  相似文献   

6.
Juglone-induced cells of Pseudomonas putida J 1 were shown to contain two isofunctional juglone hydroxylases. Both enzymes were purified about 125-fold to homogeneity in polyacrylamide gel electrophoresis. The molecular masses of the native enzymes, as determined by Sephacryl S-200 gel filtration were 59 000 Da for enzyme 1 and 56 000 Da for enzyme 2. The molecular masses of the subunits were determined by dodecyl sulfate polyacrylamide gel electrophoresis as 25 000 Da (enzyme 1) and 23 500 Da (enzyme 2). Both enzymes hydroxylated juglone, naphthazarin, 1,4-naphthoquinone and 2-chloro-1,4-naphthoquinone, but they were completely inactive against naphtholes. The activity of both hydroxylases was not affected by chelating agents, thiol reagents, however, were found to be strong inhibitors. No external cofactors such as Fe2, NADH, NADPH, FAD, FMN were required for activity. Concomitant with the hydroxylation of juglone the consumption of oxygen in a molar ratio 2: 1 (juglone: oxygen) was observed but none of the enzymes incorporated 18O2 into the substrate juglone. By activity staining enzyme 1 was found to be present in induced and non-induced cells of P. putida J 1, enzyme 2, however, only in juglone-induced cells.  相似文献   

7.
Three lectin fractions were obtained from seeds of the leguminous plant Cytisus scoparius (Scotch broom) by means of affinity chromatography on a N-acetyl-D-galactosamine medium. The first fraction, termed CSIa, was equally well inhibited in haemagglutination experiments by D-galactose and by N-acetyl-D-galactosamine and consisted of a group of isolectins formed from closely related polypeptide chains of approx. Mr 30000. The second fraction, CSIb, was closely related to CSIa in specificity, c.d. and other properties. The third fraction contained a homogeneous lectin, CSII, formed from subunits again of approx. Mr 30000. CSII was 100 times more readily inhibited by N-acetyl-D-galactosamine than by D-galactose. Despite the similarity in specificity, comparative studies of their amino acid composition, c.d. and N-terminal amino acid sequence showed that the CSIa and CSII lectins diverged considerably in structure. The lectin from Cytisus sessilifolius, specific for chitobiose, was also examined and resembled CSIa in composition and c.d. properties.  相似文献   

8.
Two fish aminopeptidases designated as aminopeptidases I and II were purified by DEAE-cellulose chromatography, gel filtration on Sephadex G-200, and isoelectric focusing. The final preparations of enzymes I and II were judged nearly homogenous by polyacrylamide gel I, electrophoresis. The molecular weights of enzymes I and II were determined by gel filtration to be 370,000 and 320,000, respectively. The isoelectric points were 4.1 (I) and 4.8 (II), Both enzymes were inhibited by EDTA and activated by Co++. Bestatin could inhibit enzyme I but not enzyme II. Enzymes I and II rapidly hydrolyzed not only synthetic substrates containing alanine or leucine but also di-, tri-, and tetra-alanine. Judged from all of these properties, sardine aminopeptidases resemble human alanine aminopeptidase. Enzyme I retained more than 70% of its original activity in 15% NaCl, suggesting the enzyme participates in hydrolyzing fish proteins and peptides during fish sauce production.  相似文献   

9.
Acid phosphatase associated with rat liver lysosomal membranes (M-APase) was purified about 4,200-fold over the homogenate with 10% recovery to apparent homogeneity, as determined from the pattern on polyacrylamide gel electrophoresis in the presence of SDS. The purification procedure included; preparation of lysosomal membranes, solubilization of the membranes with 1% Triton X-100, immunoaffinity chromatography, and gel filtration with FPLC equipped with a Sephacryl S-300HR column. The molecular weight, estimated by gel filtration through TSK SW 3000G, was approximately 320K and SDS gel electrophoresis showed that the enzyme is composed of four identical subunits with an apparent molecular weight of 67K. The enzyme contains about 24.3% carbohydrate consisting of mannose, galactose, fucose, N-acetylglucosamine, N-acetylgalactosamine, and N-acetylneuraminic acid in a molar ratio of 38:20:5:36:4:11, respectively. In addition, three soluble forms of acid phosphatase (C-APase I, II, and III) in lysosomal contents were separated from rat liver lysosomal contents with DEAE-Sephacel. These three enzymes were also purified using immunoaffinity chromatography followed by gel filtration. C-APase I, II, III, and M-APase have isoelectric points of 7.7-8.2, 6.6-7.0, 5.7-6.7, and 3.4-3.8, respectively. All four APases are sensitive to endo-beta-N-acetylglucosaminidase H. However, only C-APase III and M-APase are digestible with neuraminidase. Susceptibility of M-APase to neuraminidase in intact tritosomes was examined to study the topography of M-APase in tritosomal membranes. Neuraminidase susceptibility of M-APase was not observed in the intact tritosomes until the tritosomes had been disrupted by osmotic shock.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Incubation of galactose treated Kluyveromyces bulgaricus yeast cells in EDTA/phosphate-buffered saline led to an extract possessing hemagglutinating and yeast flocculating properties. Purification of this extract by affinity chromatography and gel filtration gave two lectin forms, Kb-CWL I and Kb-CWL II, with an apparent molecular mass of 38,000 and 150,000 Da, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that Kb-CWL I and Kb-CWL II were dimeric and octameric of a subunit of 18,900 Da. At high concentration, purified Kb-CWL I associated to give Kb-CWL II. This association seemed to be independent on pH. The two lectin forms were glycoproteins, the peptide counterpart was very rich in Lys, Glu, and Gly, and the carbohydrate part represented 1% of the whole molecule and was composed of Glc, Man, and Ara. The two lectin forms (KB-CWL I and Kb-CWL II) agglutinated human red blood cells and flocculated EDTA-treated K. bulgaricus yeast cells. The activity of both lectin forms required Ca2+ ions, while Sr2+ showed some competitive inhibition. Optimal activity was obtained within a pH range of 4-6.5 for both forms. Temperatures of 80-90 degrees C for 20 min, or proteolytic treatment reduced irreversibly the activity of Kb-CWL I and Kb-CWL II. The role of the cell wall phosphopeptidomannan as a ligand and a potential physiological receptor of these lectin forms was demonstrated.  相似文献   

11.
Three lectins were extracted and purified from mulberry seeds by gel filtration of 100% ammonium sulfate saturated crude protein extract followed by ion-exchange chromatography on DEAE and CM-cellulose. The lectins were found to be homogeneous as judged by polyacrylamide disc gel electrophoresis. The molecular masses of the lectins as determined by gel filtration were 175 000 for MSL-1, 120 000 for MSL-2 and 89 500 for MSL-3. MSL-1 is dimer in nature, with the two monomers held together by disulfide bond(s), while MSL-2 and MSL-3 contain four nonidentical subunits that are held together by nonionic hydrophobic interactions. The lectins agglutinated rat red blood cells and this agglutination was inhibited specifically by galactose, methyl-alpha-d-galactopyranoside, methyl-beta-d-galactopyranoside, lactose and raffinose. The lectins MSL-1, MSL-2 and MSL-3 contained 5.7, 5.4 and 4.5% neutral sugars, respectively, and the sugar composition of the lectins was glucose and mannose for MSL-1 and galactose for both MSL-2 and MSL-3. The lectins exhibited strong cytotoxic effect in brine shrimp lethality bioassay.  相似文献   

12.
Four lectins were purified from a mushroom (Agaricus bisporus) by ammonium sulfate fractionation, anion-exchange chromatography, affinity chromatography on bovine submaxillary mucin-Sepharose 4B and preparative isoelectric focusing. They were designated as ABA-I (pI 6.70), II (pI 5.98), III (pI 5.69) and IV (pI 5.53). Polyacrylamide gel electrophoresis of each lectin in the presence of sodium dodecyl sulfate gave a single band with an apparent molecular mass of 16 000 Da. Sedimentation equilibrium analysis suggested that each lectin is a tetramer of subunits. The four lectins were found to have quite similar carbohydrate-binding specificities. The hemagglutination activities of the lectins were effectively inhibited by bovine and porcine submaxillary mucins (BSM and PSM), and NH2-terminal glyco-octapeptides obtained by cyanogen bromide cleavage of human erythrocyte glycophorin A. In addition, desialylated PSM-glycopeptides were more potent inhibitors than untreated PSM-glycopeptides. Among monosaccharides and their glycosides, only methyl N-acetyl-alpha-galactosaminide inhibited lectin binding at a high concentration, but a synthetic oligosaccharide, O-beta-galactopyranosyl-(1----3)-O-(2-acetamido-2-deoxy-alpha-D- galactopyranosyl)-N-tosyl-L-serine, was a strong inhibitor.  相似文献   

13.
A new type lactose-binding lectin was purified from extracts of Ulex europaeus seeds by affinity chromatography on a column of galactose-Sepharose 4B, followed by gel filtration on Sephacryl S-300. This lectin, designated as Ulex europaeus lectin III (UEA-III), was found to be inhibited by lactose. The dimeric lectin is a glycoprotein with a molecular mass of 70,000 Da; it consists of two apparently identical subunits of a molecular mass of 34,000 Da. Compositional analysis showed that this lectin contains 30% carbohydrate and a large amount of aspartic acid, serine and valine, but no sulfur-containing amino acids. The N-terminal amino-acid sequences of L-fucose-binding Ulex europaeus lectin I (UEA-I) and di-N-acetylchitobiose-binding Ulex europaeus lectin II (UEA-II), both of which we have already purified and characterized, and that of UEA-III were determined and compared.  相似文献   

14.
Midgut glands of abalone Haliotis discus contained two acid phosphatases [orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2] separable by phosphocellulose column chromatography. They were designated as acid phosphatases I and II in order of elution and were purified 99- and 290-fold, respectively. Purified acid phosphatase II was nearly homogeneous as judged by polyacrylamide gel electrophoresis. The substrate specificity of acid phosphatase I was narrow, whereas that of acid phosphatase II was broad. Good substrates for acid phosphatase I included p-nitrophenyl phosphate, phosphoenolpyruvate, inorganic pyrophosphate, and nucleoside di- and triphosphates. The acid phosphatases did not require any metal ion for maximum activity and were inhibited by Zn2+, Cu2+ and Hg2+. Fluoride and arsenate were potent inhibitors of both enzymes. The pH optima of acid phosphatases I and II were 5.9 and 5.5, respectively. The molecular weights of acid phosphatases I and II were estimated to be 28,000 and 100,000, respectively, by gel filtration on Sephadex G-100. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggested that acid phosphatase II consists of two identical subunits.  相似文献   

15.
The brine shrimp, Artemia, an inhabitant of coastal and inland salterns, encounter fluctuations in the salinity which in turn influences the oxygen availability of their habitat. Hence, experiments were performed to analyze variations in haemoglobin structure and patterns of three strains of Artemia from South India and also to reflect the effect of varying oxygen levels in their habitat. Haemoglobins were purified on a DEAE-Sephadex column and haemoglobin types were analyzed by comparing their relative mobility on a non-denaturing medium. Furthermore, their molecular masses were determined by gel filtration in Sepharose column and by dodecylsulfate polyacrylamide gel electrophoresis. Results clearly reveal the presence of three distinct extracellular haemoglobins Hb I, Hb II and Hb III in Tuticorin strain while the other strains displayed only trails or the complete absence of Hb III and Hb II. Estimated molecular masses of these haemoglobins are 235,000-250,000 Da. Denaturation of the reduced and alkylated haemoglobins revealed apparently one polypeptide chain with a molecular mass of 124,000 Da. Upon denaturing gel electrophoresis of native haemoglobin Hb II, it was found that the 124,000 Da, polypeptide was cleaved specifically into two unequally-sized fragments of 50,400 and 79,800 Da. With regard to oxygen affinity, Hb III has a very high affinity for oxygen, an almost negligible Bohr effect and a good physiological adaptation to temperature changes. By combining the three haemoglobins in different proportions Artemia strains must be able to withstand diverging environmental conditions. In particular, the absence of Hb III in Puthalam and its occurrence as a faint band in Thamaraikulam could be correlated to the oxygen levels of their habitats.  相似文献   

16.
A beta-galactoside-binding activity has been detected in mammalian brain extracts using a hemagglutination test and a nerve cell aggregation assay. Inhibition studies suggested the involvement of lectin-carbohydrate interactions in these processes. In an attempt to explore further the biological role of brain lectins, the beta-galactoside-binding activity has been purified to apparent homogeneity from bovine and rat brain by salt extraction of the brain tissue and affinity chromatography on asialofetuin-agarose. The molecular weights determined by gel filtration, under native conditions on Ultrogel AcA-34, were 30,000 for the bovine brain lectin and 32,000 for the rat brain lectin; polyacrylamide gel electrophoresis in SDS gave molecular weights of 15,000 and 16,000, respectively, suggesting that the two brain lectins are dimers. Both lectins have an isoelectric point of 3.9. Amino acid composition data indicate that both lectins contain high proportions of glycine and acidic amino acids. The lectins are specific for beta-D-galactosides and related sugars and the configuration of carbon atoms 1, 2 and 4 seems of primary importance. Moreover, the nerve cell aggregation-promoting activity of the purified lectin is 300-fold that of the crude extracts.  相似文献   

17.
A mouse macrophage cytotoxic factor was purified to homogeneity from the serum-free culture supernatant of a mouse macrophage hybridoma clone, N/P-7-1, stimulated with lipopolysaccharide by gel filtration, affinity chromatography, anion-exchange chromatography, and polyacrylamide gel electrophoresis. The purified material was judged to be homogeneous as to the criteria of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and has a relative molecular mass of 17,500, as determined by SDS-PAGE, or 55,000, as determined by gel filtration on columns of both Sephacryl S-200 and TSK G3000SW. It has an isoelectric point of 5.0, and is trypsin sensitive, stable at 56 degrees C and labile at pH less than 6. The cytotoxic activity of the purified factor could not be inhibited by various sugars and lectins. The production of the factor from N/P-7-1 triggered by macrophage-activating factor for cytotoxicity, but not by mouse recombinant gamma-interferon. The factor should be synthesized after lipopolysaccharide stimulation because treatment of N/P-7-1 cells with a metabolic inhibitor, emetine or actinomycin D, prevents the production.  相似文献   

18.
A protein released into the culture medium by omental preadipocytes of massively obese persons, which stimulates the replication of rat perirenal preadipocytes, has been purified to a high degree. By gel filtration chromatography, the molecular mass of the mitogenic protein was approximately 66,000 daltons (Da), while on sodium dodecyl sulfate - polyacrylamide gel electrophoresis, two subunits were obtained, relative masses (Mr) of approximately 31,000 and approximately 35,000. The isoelectric point of the approximately 66,000 Da entity was 5.6 +/- 0.2. By specific radioreceptor assay, the purified protein was related to epidermal growth factor and transforming growth factor alpha. It was not related to insulin-like growth factors I and II by radioimmunoassay and radioreceptor assay. We propose that the approximately 66,000 Mr protein, and other mitogenic proteins released by preadipocytes from massively obese persons, act through paracrine-autocrine mechanisms and may play a role in the development of the hyperplasia of enlarged fat cells characteristic of massive corpulence.  相似文献   

19.
A β-galactoside-binding activity has been detected in mammalian brain extracts using a hemagglutination test and a nerve cell aggragation assay. Inhibition studies suggested the involvement of lectin-carbohydrate interactions in these processes. In an attempt to explore further the biological role of brain lectins, the β-galactoside-binding activity has been purified to apparent homogeneity from bovine and rat brain by salt extraction of the brain tissue and affinity chromatography on asialofetuin-agarose. The molecular weights determined by gel filtration, under native conditions on Ultrogel AcA-34, were 30 000 for the bovine brain lectin and 32 000 for the rat brain lectin; polyacrylamide gel electrophoresis in SDS gave molecular weights of 15 000 and 16 000, respectively, suggesting that the two brain lectins are dimers. Both lectins have an isoelectric point of 3.9. Amino acid composition data indicate that both lectins contain high proportions of glycine and acidic amino acids. The lectins are specific for β-D-galactosides and related sugars and the configuration of carbon atoms 1, 2 and 4 seems of primary importance. Moreover, the nerve cell aggregation-promoting activity of the purified lectin is 300-fold that of the crude extracts.  相似文献   

20.
We have isolated by affinity chromatography a lectin from the seeds of the winged bean (Psophocrapus tetragonolobus) which agglutinated human (group A, B and O), sheep and rabbit, but not mouse erythrocytes. A molecular weight of 41,000 was obtained from gel filtration, and on sodium dodecyl sulphate polyacrylamide gel electrophoresis a single polypeptide chain of molecular weight 35,000 was seen both before and after reduction. Isoelectric focussing of the lectin on polyacrylamide gel gave a single band with a calculated isoelectric point of 4.0. The lectin was found to be rich in acidic amino acids; cysteine was not detected. Carbohydrate analysis revealed no covalently bound sugars.Abbreviations PBS phosphate-buffered saline - SDS sodium dodecyl sulphate - PAGE polyacrylamide gel electrophoresis - WBL winged bean lectin - HPLC high performance liquid chromatography  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号