Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The precursor of fusion protein (Fo) in Sendai virus growth in Vero cells can be cleaved by trypsin to forms F1 and F2, which can be resolved on SDS-polyacrylamide gels. However, if disulfide bonds are preserved during electrophoresis, F1 and F2 remain linked together even after trypsin treatment (F). Sendai virus growth in embryonated chicken eggs does not contain the precursor Fo. However, an F protein was found for Sendai virus grown in eggs when disulfide bonds were preserved during electrophoresis. The hemagglutinin-neuraminidase (HN) glycoproteins also appear to be disulfide-linked to form large complexes which are observed on SDS-polyacrylamide gels of nonreduced samples.
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PMID:Disulfide bonds in Sendai virus glycoproteins. 22 8

CSF was prepared by the growth of L cells in serum-free culture medium. This conditioned medium was subjected to a six-step purification schedule which included ultrafiltration, alcohol precipitation, and separation by DEAE-cellulose, Con A-Sepharose, Sephadex G-150, and sucrose density-gradient centrifugation. The resultant CSF was 1000-fold purified with 50% to 70% recovery of the starting activity. Granulocyte and macrophage colony formation was detected with 5 x 10(-12M CSF; maximum colonies were obtained with 3 ng per marrow culture. Two major peaks of activity were obtained; one was nonadherent to Con A, whereas the other was bound and specifically eluted with alpha-methylglucoside. Both fractions contained carbohydrate residues as they stained avidly with PAS, were inactivated by periodate, and showed altered electrophoretic mobility after treatment with neuraminidase. Following iodination, each purified fraction migrated in a single band in SDS-acrylamide gels. The molecular weight was estimated as 65,000 to 70,000 daltons. Following reduction with mercaptoethanol, the CSF fractions were reduced into subunits with molecular weights of approximately 35,000. These studies confirm the glycoprotein nature and subunit composition of L cell CSF. The methods described herein are useful for the purification of both the Con A-adherent and con A-nonadherent forms of CSF.
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PMID:Purification and properties of L cell-derived colony-stimulating factor. 31 66

Samples of homozygous bovine serum transferrins have been prepared and their purity has been ascertained by immunological techniques and electrophoretic analysis in SDS. Measurements of carbohydrate composition show that no significant differences exist among the phenotype variants AA, D1D1, D2D2, and EE. Chromatography of transferrin AA on DEAE-cellulose separated four subfractions, each of which corresponded well with one band obtained by polyacrylamide gel electrophoresis. Carbohydrate analyses of the individual subfractions did not show significant differences in sialic acid, hexose, or hexosamine contents. After desialylation with neuraminidase, each subfraction was converted to a major band and a minor band on gel electrophoresis. From the relative band positions of the desialylated transferrins, it was concluded that possession of sialyl residued by bovine transferrin is not the primary cause of electrophoretic multiplicity. Rather, sialic acid masks an underlying heterogeneity which most likely resides within the polypeptide chain. Further characterization of this heterogeneity will best be undertaken with the isolated asialotransferrin subfractions.
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PMID:Bovine serum transferrin phenotypes AA, D1D1, D2D2, EE: their carbohydrate compositions and electrophoretic multiplicity. 92 36

A glycoprotein was isolated from goat erythrocyte membranes by extraction with hot 75% ethanol. The glycoprotein was purified by ethanol precipitation, phosphocellulose chromatography gel filtration, ethyl:ether and chloroform:methanol extraction. In aqueous phosphate-buffered saline, pH 7, the glycoprotein was in an aggregated state with a sedimentation coefficient (S(obs)) to 1.5. Electrophoresis of the glycoprotein on polyacrylamide gels containing phosphate-buffered 0.1% SDS gave a single band, staining with both periodic acid Schiff (PAS) and Coomassie Blue (CB). The apparent m.w., calculated from retardation coefficient, was 25,000. Electrophoresis of the glycoprotein on 1% SDS gels buffered with Tris-acetate (pH 7.4) showed a major band of similar (23,500) apparent m.w. plus four other PAS- and CB-staining bands of lower mobility. With 131I-labeled glycoprotein, recovery of bands from gels, sialic acid analysis, heterophile antigen activity, and re-electrophoresis, it was shown that these additional bands were aggregated forms of a single or closely related glycoprotein species. The purified glycoprotein contained 50% carbohydrate with molar ratios of sialic acid:galactose:mannose:galactosamine:glucosamine of 3.1:2.1:0.1:1.6:1. The glycoprotein was highly reactive with the Paul-Bunnell heterophile antibody in the sera of patients with infectious mononucleosis, with Limulus polyphemus lectin and weakly ractive with wheat germ agglutinin. These reactivities were destroyed by neuraminidase treatment or by alkaline sodium borohydride. The native glycoprotein did not react with lectins from Canavalia enisformis, Phaseolus vulgaris, Ricinus communis, or Vicia graminea although it was reactive with the latter two after neuraminidase treatment.
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PMID:Immunochemical studies of infectious mononucleosis. V. Isolation and characterization of a glycoprotein from goat erythrocyte membranes. 95 50

Analyses of the polypeptide composition of influenza B viruses by 13 per cent SDS-polyacrylamide gel electrophoresis are reported. The viruses contained polypeptides of eight species ranging in molecular weight from 27,000 to 78,000. Four of them were glocypeptides and were selectively removed from the surface of the virion by Bromelain treatment. One of the blycopeptides was identified as viral neuraminidase. Three antigenically distinct strains of influenza virus, B/Lee/40, B/Massachusetts/1/71 and B/Hong Kong/5/72, showed an essentially identical electrophoretic picture, although strain-to-strain difference was observed in the migration rate of HA1 and HA2 polypeptides.
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PMID:Structural polypeptides of antigenically distinct strains of influenza B virus. 113 2

Milk fat globule membrane was solubilized with sodium dodecyl sulfate and mercaptoethanol and the membrane proteins were separated by SDS-polyacrylamide gel electrophoresis. The membrane preparations contained three major size classes of polypeptide of 155,000, 62,500 and 43,500 daltons. At least five glycopeptides were separated of which two stained intensely with periodic acid-Schiff reagent, but poorly with coomassie blue. Trypsin hydrolysis of whole cream and isolated milk fat globule membrane revealed major differences in the rates of protein hydrolysis. Many of the membrane proteins of whole cream resisted proteolysis compared with the same proteins in the isolated membrane. Two glycopeptides were resistant to trypsin digestion in either preparation. Treatment of whole cream with neuraminidase led to the release of at least 70% of the protein-bound sialic acid. Whole cream and isolated membrane samples were iodinated with 125I in the presence of lactoperoxidase and hydrogen peroxide. The membrane proteins were significantly more accessible to lactoperoxidase-125I i in isolated membrane compared with the proteins of whole cream. Polypeptides of molecular weight 43,500 and approximately 48,000 daltons were predominantly labelled in whole cream and could be eluted from the fat globules with magnesium chloride (1.5m). The results strongly suggest that the proteins of milk fat globule membrane are asymmetrically arranged in the membrane and that most of the protein-bound sialic acid is present on the external surface of milk fat globules.
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PMID:Studies on the structure of milk fat globule membrane. 119 40

A simple and reproducible method for the production of purified rubella virus is described. Purified virus was subjected to morphological and chemical analysis. The virus particles were rather pleomorphic (60 nm diameter), sometimes with one or more peripheral protrusions. The viral surface, revealed by negative staining, was composed of spikes 6 nm long, featuring enlarged ends. In SDS-urea-polyacrylamide gel electrophoresis, 4 major and 4 minor polypeptide bands were revealed. Total lipids and phospholipids were analysed on the same preparation. The viral particles were composed of RNA: 0.030 mg, and lipids: 0.245 mg, of which 0.169 mg were phospholipids for each mg of viral protein. Biologically, the purified virus preparation showed high infectivity, a high hemagglutination titre and a weak neuraminidase activity under defined conditions.
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PMID:Morphology, biochemical analysis and neuraminidase activity of rubella virus. 121 96

An enzymatic procedure for the complete removal of the N-linked and O-linked oligosaccharide side chains of the sex steroid-binding proteins (SBP or SHBG) of human and rabbit plasma under native conditions is described. Deglycosylation was catalyzed by N-glycanase, neuraminidase, and O-glycanase and was monitored by SDS-PAGE, lectin blotting, and molecular weight analyses by electrospray mass spectrometry. Digestion of rabbit SBP with N-glycanase generated a major 39,777-Da protein and two minor ones of 39,389 and 39,545 Da. The molecular weight of the major protein agrees with the molecular weight calculated from the sequence of the sugar-free polypeptide monomer (39,769 Da: Griffin, P.R., Kumar, S., Shabanowitz, J., Charbonneau, H., Namkung, P.C., Walsh, K.A., Hunt, D.F., & Petra, P.H., 1989, J. Biol. Chem. 264, 19066-19075), whereas the other two are deglycosylated proteolytic cleavage products lacking the TQR and TQ sequences at the amino-terminus. The N- and O-linked side chains of human SBP were removed by sequential digestion with N-glycanase and neuraminidase/O-glycanase. A 38,771-Da protein was generated, which agrees well with the molecular weight of the sugar-free polypeptide monomer (Walsh, K.A., Titani, K., Kumar, S., Hayes, R., & Petra, P.H., 1986, Biochemistry 25, 7584-7590). N-deglycosylation of human and rabbit SBP has no effect on the steroid-binding activity, but removal of the O-linked side chains of N-deglycosylated human SBP results in an apparent 50% loss of steroid-binding activity and an increase in the Kd for the binding of 5 alpha-dihydrotestosterone from 0.3 mM to 0.9 nM.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Complete enzymatic deglycosylation of native sex steroid-binding protein (SBP or SHBG) of human and rabbit plasma: effect on the steroid-binding activity. 130 75

The biosynthesis of MHC Class II molecules starts with the assembly of the alpha and beta subunits and the invariant chain. Intracellular transport of Class II molecules was followed in pulse-chase experiments of a human Epstein-Barr virus-transformed B lymphoblastoid cell line. Entry of Class II molecules into the endocytotic pathway and their cell surface appearance were monitored using neuraminidase as a fluid endocytotic marker and as a surface probe, respectively. In the course of intracellular transport, the Class II associated invariant chain is removed by proteases located in the endosomal pathway. Here, we show that leupeptin inhibits not only invariant chain breakdown, but also surface deposition of newly synthesized Class II molecules. Class II molecules display remarkable resistance to SDS at ambient temperature when occupied by peptide. We exploit this property to show that peptide binding precedes surface expression, and takes place in the course of intracellular transport through an endosomal compartment. Leupeptin blocks the conversion of Class II molecules to an SDS resistant complex.
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PMID:Inhibition of endosomal proteolytic activity by leupeptin blocks surface expression of MHC class II molecules and their conversion to SDS resistance alpha beta heterodimers in endosomes. 131 Dec 49

Several high-density lipoprotein (HDL)-binding proteins, candidates for the putative HDL receptor, have recently been identified, including two membrane proteins: HB1 of 120 kDa and HB2 of 100 kDa, present in rat and human liver plasma membranes respectively. Further insights into their function however, have been hampered by poor recoveries of these hydrophobic peptides, and the present work was undertaken to improve yields and enable a more detailed investigation of their properties. A significant improvement has been achieved using two affinity chromatographic procedures, one exploiting the glycoprotein nature of the proteins and the other exploiting their ligand properties, which in combination resulted in considerable enrichment of HB1 and HB2. Thus DEAE-Sephacel fractionation (0.05-0.2 M-NaCl) of CHAPS-solubilized plasma membranes yielded active HDL-binding proteins which bound to concanavalin A-Sepharose or wheat-germ-lectin-Sepharose columns and retained their binding activity after eluting with methyl-alpha-D-mannoside or N-acetylglucosamine respectively. These glycoproteins were further purified by affinity chromatography using apo-HDL-Sepharose columns. Final purification required preparative SDS/PAGE. Investigation of the carbohydrate moieties of the proteins using glycosidases and two-dimensional gel electrophoresis revealed pI values ranging from 4.6 to 4.9 and from 4.5 to 4.7 for HB1 and HB2 respectively, which after treatment with neuraminidase shifted towards basic pH (5.4-5.7 and 5.3-5.5 respectively). The molecular masses were decreased to 115 kDa and 95 kDa respectively, demonstrating that sialic acid residues contributed significantly to the negative charge of the glycosylated peptides. Treatment with the enzyme peptide N-glycosidase F (N-glycanase) resulted in a decrease in molecular mass of HB1 and HB2 to 105 kDa and 80 kDa respectively, but endo-alpha-N-acetylgalactosaminidase (O-glycanase) treatment was not effective. Neither neuraminidase nor N-glycanase treatment destroyed activity, suggesting that sialic acids or N-linked oligosaccharides are not important determinants of HDL binding. Digestion of plasma membranes with trypsin or Pronase resulted in a loss of activity of both HB1 and HB2 that was not influenced by prior treatment with neuraminidase, suggesting that sialic acid residues play no protective role against proteolytic cleavage of HDL receptor proteins.
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PMID:Affinity purification of the hepatic high-density lipoprotein receptor identifies two acidic glycoproteins and enables further characterization of their binding properties. 131 18


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