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)

Lysosomal neuraminidase (sialidase; EC 3.2.1.18) and beta-galactosidase (EC 3.2.1.23), together with a carboxypeptidase, the so-called 'protective protein', were co-purified from the human placenta by affinity chromatography on a concanavalin A-Sepharose column followed by a thiogalactoside-agarose affinity column for beta-galactosidase. Analysis of the purified material by gel-filtration h.p.l.c. revealed three distinct molecular forms, all with high beta-galactosidase specific activity, but only the largest one expressed neuraminidase activity. Rechromatography of each individual species separately indicated that all three are in fact part of an equilibrium system (the neuraminidase-beta-galactosidase-carboxypeptidase complex or NGC-complex) and that these species undergo slow conversion into one another through dissociation and association of protomeric components. Each species was sufficiently stable for the determination of their hydrodynamic properties by gel-filtration h.p.l.c. and sedimentation velocity. The largest species had an apparent sedimentation coefficient S20.w, of 18.8 S and a Stokes' radius of 8.5 nm, giving a molecular mass of 679 kDa and a fractional ratio, f/f min, of 1.47. The latter value indicates that the macromolecule is asymmetric or highly hydrated. This large species is composed of four types of polypeptide chains of molecular mass 66 kDa (neuraminidase), 63 kDa (beta-galactosidase), 32 kDa and 20 kDa (carboxypeptidase heterodimer). The 32 kDa and 20 kDa protomers are linked together by a disulphide bridge. Glycopeptidase F digestion of the NGC-complex transformed the diffuse 66-63 kDa band on the SDS gel into two close but sharp bands at 58 and 56 kDa. The two smaller species which were separated on the h.p.l.c. column correspond to tetrameric and dimeric forms of the 66-63 kDa protomers and express exclusively beta-galactosidase activity. Treatment of the NGC-complex with increasing concentrations of guanidinium hydrochloride up to 1.5 M also resulted in dissociation of the complex into the same smaller species mentioned above plus two protomers of molecular mass around 60 and 50 kDa. A model of the largest molecular species as a hexamer of the 66-63 kDa protomers associated to five carboxypeptidase heterodimers (32 kDa and 20 kDa) is proposed
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PMID:Structure of the lysosomal neuraminidase-beta-galactosidase-carboxypeptidase multienzymic complex. 210 3

The low density lipoprotein receptor-related protein (LRP) is a cell surface glycoprotein that binds and transports plasma lipoproteins enriched in apolipoprotein E. It is synthesized in the endoplasmic reticulum as a transmembrane glycosylated precursor that migrates with an apparent molecular mass of about 600 kd on SDS-polyacrylamide gels. After it reaches the Golgi complex, the protein is cleaved to generate two subunits with apparent molecular masses of approximately 515 and 85 kd respectively. The larger NH2-terminal alpha-subunit lacks a membrane-spanning region. It remains attached to the membrane through noncovalent association with the smaller COOH-terminal beta-subunit. Proteolysis occurs at the sequence RHRR, which resembles the sequence RKRR at the proteolytic site in the receptors for insulin and insulin-like growth factor-1 (IGF-1), the only other cell surface receptors known to undergo proteolytic processing. Proteolysis of LRP occurs coincident with the conversion of the N-linked carbohydrates to the mature endoglycosidase H-resistant, neuraminidase-sensitive form. Proteolysis is prevented by brefeldin A, which blocks transport to the Golgi complex. These data raise the possibility that LRP and the receptors for insulin and IGF-1 are processed by a specific endoprotease that recognizes protein with extended basic sequences and resides in the trans-Golgi complex or in post-Golgi vesicles of the constitutive secretory pathway.
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PMID:Proteolytic processing of the 600 kd low density lipoprotein receptor-related protein (LRP) occurs in a trans-Golgi compartment. 211 85

Changes of the three types, termed here as alpha, beta and gamma, in the secretory functions present in the submandibular glands (SMG) of male rats were observed throughout almost all animal lives from 2 weeks to 24 months of age, by measuring changes of the wet weights of the SMG, salivary volumes secreted, the concentrations of protein, calcium and inorganic phosphate, and the types of proteins secreted in response to alpha-methylnoradrenaline (alpha-mNA) for the alpha-type, isoproterenol (IPR) for the beta-type and clonidine (Clonid) for the gamma-type, volumetrically, colorimetrically, atomic absorption-pectrophotometrically and isoelectric focusing electrophoretically. The molecular weight, isoelectric point and some posttranslational variations of a purified protein were elucidated by SDS-polyacrylamide gel electrophoresis (PhastSystem), isoelectric focusing electrophoresis (IEF, PhastSystem) on gradient pH 3.5 to 5 gels and neuraminidase or alkaline phosphatase treatment. The localization in the SMG, the inhibitory effects on the BrdU incorporation of the cultured thymocytes and the adhesive properties to the acrylic resin plate of this antigen were also analyzed by the indirect immunofluorescence, IEF and protein detection methods. The wet weights of the SMG were substantially increased up to 3.5 months of age with a positive correlation to body weight, but thereafter it reached the plateau level up to 24 months of age, somewhat different from changes of body weight. The salivary volumes as well as the amounts of protein secreted in response to alpha-mNA, IPR and Clonid were positively correlated to the wet weights of the SMG throughout the animal life. The concentration of calcium in the three types of secretions was positively correlated to the protein concentration, whereas the concentration of inorganic phosphate was tended to be reversely correlated to the salivary flow rate with some exceptions throughout the animal life. The gamma-type of proteins was not greatly changed, whereas the alpha- and beta-types of proteins were greatly changed in some proteins quantitatively or qualitatively throughout the animal life.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Changes of three types in the secretory systems present in the rat submandibular glands during aging]. 213 43

Mo3 is an activation Ag expressed by human monocytic cells after stimulation in vitro by PMA, LPS, certain cytokines, and muramyl dipeptide. The structural characterization of Mo3 has been made possible by the development of a mAb (anti-Mo3f) that immunoprecipitates Mo3 from Nonidet P-40 lysates of radiolabeled PMA-stimulated U-937 cells and LPS-activated monocytes. On SDS-PAGE (nonreducing conditions) of anti-Mo3f immunoprecipitates, U-937 Mo3 is a single broad band of 39 to 66 kDa, whereas monocyte Mo3 is smaller with an apparent molecular mass of 32 to 56 kDa. Under reducing conditions, there is an increase in the m.w. of both species of Mo3 suggesting the existence of internal disulfide bonds. Mo3 is a glycoprotein with carbohydrate of the N-linked complex type as evidence by a reduction in m.w. by 40 to 50% after treatment with endoglycosidase F or N-glycanase; neuraminidase treatment produces a 3-kDa reduction in m.w. Deglycosylated Mo3 isolated from U-937 and monocytes have similar m.w. suggesting that the molecular heterogeneity of the native Mo3 may be due to differences in glycosylation. Mo3 is sensitive to phosphatidylinositol-specific phospholipase C with the release of native Mo3 from the surface of PMA-stimulated U-937 cells. These results indicate that Mo3 is a member of the glycosylphosphatidylinositol-linked family of surface glycoproteins.
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PMID:A structural characterization of the Mo3 activation antigen expressed on the plasma membrane of human mononuclear phagocytes. 213 44

This paper describes a large-scale purification procedure of the amiloride binding component of the epithelium Na+ channel. [3H]Phenamil was used as a labeled ligand to follow the purification. The first two steps are identical with those previously described [Barbry, P., Chassande, O., Vigne, P., Frelin, C., Ellory, C., Cragoe, E. J., Jr., & Lazdunski, M. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 4836-4840]. A third step was a hydroxyapatite column. The purified material consisted of a homodimer of two 88-kDa proteins that migrated anomalously in SDS-PAGE to give an apparent Mr of 105,000. Deglycosylation by treatment with neuraminidase and endoglycosidase F or with neuraminidase and glycopeptidase F indicated that less than 5% of the mass of the native receptor was carbohydrate. Sedimentation analysis of the purified Na+ channel in H2O and D2O sucrose gradients and gel filtration experiments led to an estimated molecular weight of the [3H]phenamil receptor protein-detergent-phospholipid complex of 288,000 and of the native [3H]phenamil receptor protein of 158,000. [3H]Br-benzamil is another labeled derivative of amiloride that recognized binding sites that had the same pharmacological properties as [3H]phenamil binding sites and that copurified with them. Upon irradiation of kidney membranes, [3H]Br-benzamil incorporated specifically into a 185-kDa polypeptide chain under nonreducing electrophoretic conditions and a 105-kDa protein under reducing conditions. The same labeling pattern was observed at the different steps of the purification. Reconstitution of the purified phenamil receptor into large unilamellar vesicles was carried out. A low but significant phenamil- and amiloride-sensitive electrogenic Na+ transport was observed.
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PMID:[3H]phenamil binding protein of the renal epithelium Na+ channel. Purification, affinity labeling, and functional reconstitution. 216 Feb 71

Bovine plasma protein C inhibitor was purified; it was then characterized in comparison with human protein C inhibitor. The specific inhibitory activity of the purified inhibitor for bovine activated protein C was 8,500 times that of the inhibitor in plasma. The purified inhibitor showed a single band with Mr 56,000 by SDS-PAGE at pH 7.0, and two bands at pH 8.8, a major one with Mr 56,000 and a minor one with Mr 105,000, under both unreduced and reduced conditions. The pI range of the inhibitor was between 4.4 and 6.1. The Mr of the inhibitor was reduced by treatment with neuraminidase, O-glycanase, and also with glycopeptidase-A, suggesting that the inhibitor has both Asn-linked and Ser/Thr-linked carbohydrate chains. Twenty-seven of the NH2-terminal 49 amino acid residues of the bovine inhibitor, which lacks the first 4 residues from the NH2-terminal amino acid sequence of human inhibitor, were identical to those of the human inhibitor. The bovine inhibitor inhibited bovine and human activated protein C, human thrombin, Factor Xa, Factor XIa, and plasma kallikrein with Ki = 1.0, 5.2, 2.6, 3.0, 1.3 X 10(-8) M, and 4.5 X 10(-9) M, respectively. The inhibitory rates for activated protein C and thrombin were accelerated significantly in the presence of heparin or negatively charged dextran sulfate. However, the acceleration by heparin or dextran sulfate for the inhibition of Factor Xa, Factor XIa, and plasma kallikrein was not significant. The bovine inhibitor did not inhibit human Factor XIIa or plasmin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Bovine plasma protein C inhibitor with structural and functional homologous properties to human plasma protein C inhibitor. 216 Apr 49

Changes in salivary volumes and the three types of proteins secreted by the submandibular salivary gland (SMG) of male rats at 3.5, 5.5, 8, 12, 13, 14, 15, 19, 21 and 24 months of age in response to the beta 1-, alpha 1- and alpha 2-adrenoceptor agonists, isoproterenol (IPR), alpha-methylnoradrenaline (alpha-mNA) and clonidine (Clonid), were studied and compared by measuring the weight and by isoelectric focusing electrophoresis with the Phast System on both the gradient pH 3.5-5 and 3.5-9 gels with silver staining. A protein (protein A, tentatively termed in this study) purified by FPLC from saliva elicited by IPR was also analyzed by SDS-polyacrylamide gel electrophoresis, the immuno-thermoblotting method, carbohydrate determination and neuraminidase treatment. Unexpected findings were observed that salivary volumes, but not the protein concentration, were substantially increased by Clonid-, but not IPR-, stimulation with ages up to 24 months of age and that the three types of proteins elicited by each agonist were different during aging. The gamma-type of proteins elicited by Clonid was not greatly changed during aging, whereas several proteins at about neutral pI in the alpha-type, elicited by alpha-mNA, at 5.5 to 21 months of age and a protein A in the beta-type, elicited by IPR, at 13 to 24 months of age were greatly increased. This protein A without any carbohydrate and sialic acid, located only in the acinar cells, but not in any duct system, had a molecular weight of 16,000 and a pI of 4.05. We conclude that the secretory function of the SMG in the aged animals is in general little changed.
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PMID:Protein secretion by rat submandibular glands in response to isoproterenol, alpha-methylnoradrenaline and clonidine during aging. 221 91

In this report we describe, using a previously characterised monoclonal antibody (NC-2), the biochemical characteristics of a human leukaemia-associated alloantigen. Two proteins with molecular weights of 50 kDa and 15 kDa were immunoprecipitated from 125I surface labelled HL-60 cells. Both proteins appeared to be sensitive to digestion with trypsin, the 50 kDa protein in particular. Treatment with glycopeptidase F indicated the presence of N-linked oligosaccharides, whereas treatment with neuraminidase had no effect on the mobility of the antigens in SDS-PAGE indicating the absence of detectable sialic acid residues. Sensitivity to glycopeptidase F indicates that the reacting antigens are glycoproteins in nature. The antibody reacts with a range of normal tissues and appears to be associated with cytoplasmic granules in HL-60 cells.
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PMID:Biochemical characterisation studies on a leukocyte alloantigen expressed with high frequency in leukaemia patients. 223 48

The ability of von Willebrand factor protein (vWF) to agglutinate platelets with ristocetin depends upon the presence of its highest molecular weight multimers (HMWM) and its intact carbohydrate structure. Previously we demonstrated that the HMWM are preferentially adsorbed to purified fibrillar type I collagen. The role of the carbohydrate structure of vWF in this function has not been established. In these studies complete desialylation (greater than 95%) of the intact protein by neuraminidase did not interfere with the normal adsorption of vWF activity to type I collagen. In contrast, modification of the penultimate galactose of the desialylated protein with galactose oxidase or beta-galactosidase markedly reduced adsorption of vWF activity by collagen. Subsequent reduction of the oxidized desialylated protein with potassium borohydride completely regenerated the normal adsorption of vWF activity by collagen. Enzymatic modification of the penultimate galactose moiety of vWF resulted in a loss of the HMWM, as observed following SDS-glyoxyl agarose electrophoresis. This was in contrast to desialylated vWF, which appeared intact structurally and which predictably lost its HMWM upon exposure to collagen in a manner similar to native vWF. Therefore, the carbohydrate structure of vWF and, in particular, the penultimate galactose moiety, may be critical for vWF-collagen interactions and for the mediation of primary hemostasis.
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PMID:Critical role of the carbohydrate moiety in human von Willebrand factor protein for interactions with type I collagen. 230 Sep 25

The porcine paramyxovirus is a newly identified agent of a fatal disease in piglets, endemic in Mexico since 1980, where it was seen around the town of La Piedad, Michoacan, Mexico (hence LPM virus). At least six [35S]methionine-labelled proteins could be resolved by SDS-PAGE and five of them were clearly immunoprecipitated. Selective labelling of LPMV-infected cells with [3H]glucosamine revealed two bands with an Mr of about 66K and 59K, corresponding to the two viral glycoproteins, the haemagglutinin-neuraminidase protein and the fusion protein. Labelling of virus with [32P]orthophosphate disclosed one band with an Mr of 52K, corresponding to the phosphoprotein. Analysis of nucleocapsids obtained from purified virus or from a permanently infected cell line revealed one major band with an Mr of 68K, the nucleoprotein. Two other proteins were also identified, the large protein and the matrix protein, with apparent Mr of about 200K and 40K, respectively. The protein migration pattern of LPMV was compared, by SDS-PAGE, with that of Newcastle disease virus, bovine parainfluenza 3 virus and Sendai virus. Differences in the Mr of LPMV proteins and the proteins of these paramyxoviruses were observed. We propose that LPMV should be classified as a novel member of the genus Paramyxovirus.
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PMID:The structural proteins of a porcine paramyxovirus (LPMV). 231 67


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