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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present work we have studied the subunit composition of kinesin, the microtubule-activated, mechanochemical ATPase, isolated from bovine brain. Polypeptides with mol. wts of 120 and 62 kd are the major components of the kinesin preparation. These polypeptides could not be separated by electrophoresis under nondenaturing conditions or by FPLC on a MonoQ column, and are therefore assumed to form a tight complex. As shown by immunoblotting with polyclonal and monoclonal antibodies to the 120-kd polypeptide and by one-dimensional peptide mapping, the 62-kd polypeptide does not appear to be a proteolytic product of the 120-kd component. Densitometric scanning of polyacrylamide-SDS gels shows that these polypeptides are present in a complex in a 1:1 molar ratio. The mol. wt of native kinesin was studied by sedimentation equilibrium and was found to be 386 +/- 14 kd. A comparison of the mol. wts of individual polypeptides with the mol. wt of the intact molecule indicates that the native molecule contains two 120-kd subunits and two 62-kd subunits.
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PMID:The quaternary structure of bovine brain kinesin. 313 Feb 48

The purpose of the present report was to document the stress response produced by physical and chemical abuses to human periodontal ligament cells, and to review some of the known functions of stress response proteins produced as a result of such treatments. For these studies human PDL cells were exposed to sublethal challenges of 43 degrees C heat, sodium arsenite and the amino acid analog L-azetidine-2-carboxylic acid (AZC). The cells were labelled with [35S]-methionine and the proteins produced were examined by autofluorography of SDS-PAGE gels. Heat challenges were shown to induce hsps with an apparent mol. wts. of 90K, 68-72K, 41-47K, and 36 K. Arsenite-treated cells produced similar hsps including a 30k protein not produced by other forms of stress. AZC treatment resulted in the production of apparent functionless hsps with apparent molecular weights of 90,000, 72,000, 68,000 and 36,000. The function of these proteins and their possible role in periodontal disease is discussed.
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PMID:Expression of heat stress proteins by human periodontal ligament cells. 315 Apr 36

beta-N-Acetyl-D-hexosaminidase has been purified ca. 190-fold to homogeneity from boar seminal plasma. It catalyzed the hydrolysis of the p-nitrophenyl-N-acetyl derivatives of both beta-D-glucosaminide and beta-D-galactosaminide but was inactive with the o- or p-nitrophenyl glycosides of other monosaccharides. Its pH optimum was 4.5 and its KM was 1.5 mM with p-nitrophenyl-N-acetyl-beta-D-glucosamide as substrate. The enzyme was inhibited by mercuribenzoate compounds but not by iodoacetamide, 2,2'-dipyridyl disulfide, methylmethane thiosulfonate, nor N-ethylmaleimide. The active enzyme had mol. wt ca. 250,000 by Sephacryl S-300 chromatography. SDS electrophoresis showed single bands corresponding to subunit mol. wts ca. 62,000 and 107,000 depending on whether the enzyme had been denatured in the presence of 2-mercaptoethanol or not. These data suggest that the enzyme is a tetramer of identical subunits, pairs of which are held together by disulfide bonds.
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PMID:Purification and properties of beta-N-acetyl-D-hexosaminidase from boar seminal plasma. 316 63

Cell free supernatants prepared from amyloidotic liver, unfractionated and fractionated peritoneal and spleen cells from casein stimulated (16 h post-injection) or alveolar hydatid cyst-infected (7 or 12 weeks post-infection, p. i.) C57BL/6J mice were used to assess amyloid enhancing factor (AEF) activity and to determine its cell-source and physicochemical properties. Of the various supernatants used, the plastic adherent spleen cell lysate (95% macrophages) from 7 weeks p.i mice showed greater AEF activity, on a cell to cell basis, than the lysates prepared from whole spleen cells, peritoneal exudate cells or nonadherent (96% lymphocytes) spleen cells. Culture supernatants obtained from Con A, LPS or the parasite antigen stimulated amyloidotic spleen cells but not the normal mouse spleen cells contained AEF activity; the supernatant from unstimulated amyloidotic spleen cells was negative for AEF activity. AEF was precipitated with 25% and 50% saturation with (NH4)2SO4 and after gel-filtration the low molecular weight fraction contained the AEF activity which on SDS-PAGE resolved into three peptides ranging between mol. wts 15,000 and 31,000. Of the various specific and nonspecific protease inhibitors tested, AEF activity was completely abolished by 30 min preincubation with 10 mM phenylmethylsulphonyl fluoride. Taken together, these results indicate that AEF may be a small molecular weight lysosomal neutral protease of neutrophil/macrophage origin.
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PMID:Alveolar hydatid cyst induced amyloid enhancing factor (AEF): physicochemical properties and abolition of AEF activity by serine protease inhibitors. 316 77

Five mouse mammary epithelial cell lines (MMEC) with different growth rates were used to examine the relationship between selenoprotein levels and selenite-mediated inhibition of DNA synthesis. The inhibition of DNA synthesis preceded and was significantly greater than inhibition of protein synthesis. Cycloheximide, a protein synthesis inhibitor, caused a coordinate inhibition of both DNA and protein synthesis over a 50-fold dose range. Of the selenoproteins detected by one-dimensional SDS-PAGE, the 58-, 26- and 23-kd proteins were the only major selenoproteins observed in common among the five MMEC lines before and during inhibition of DNA synthesis. Other selenoproteins were present in some cell lines or after inhibition of DNA synthesis. The level of the 58-kd selenoprotein was most closely correlated with the degree of inhibition of DNA synthesis (r2 = 0.85), whereas the 26- and 23-kd proteins most closely correlated with selenite retention (r2 = 0.78). Upon selenite withdrawal from the growth medium, the decrease in 58-kd, but not in the 26- and 23-kd proteins correlated with resumption of DNA synthesis. Similarly, dose-response studies indicated that the 58-kd protein increased greater than 20-fold, whereas the 26- and 23-kd proteins increased only 5-fold. At high doses of selenite, other selenoproteins of mol. wts 30-101 kd were present but these proteins seemed to appear after inhibition of DNA synthesis. The possibility exists that these proteins may be product/precursors of the major selenoproteins. Since these experiments attempted to quantitate selenoproteins by densitometry of one-dimensional SDS-PAGE autoradiographs, the quality controls used for the experiments are discussed. The results are discussed in terms of the hypothesis that the 58-kd selenoproteins may mediate the effects of selenite on DNA synthesis.
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PMID:Intracellular 58-kd selenoprotein levels correlate with inhibition of DNA synthesis in mammary epithelial cells. 316 59

The urease enzyme of Campylobacter pylori was studied and compared with that of a related spiral-shaped bacterium, St1, isolated from the rodent ileum. Both bacteria possessed constitutive urease enzymes with activities up to 20-70 times that of Proteus vulgaris. This activity was retained on SDS-polyacrylamide gels. A major catalytic subunit of mol. wt 300,000 was located for all (six) strains of C. pylori subjected to SDS-PAGE whereas St1 had two active forms of mol. wts 140,000 and 150,000. Western-blot analysis indicated the presence of anti-urease antibodies in the sera of patients with C. pylori-associated gastritis. The response to C. pylori urease was not strain-specific but no cross-reactivity was detected between the C. pylori enzyme and that of St1. The very high urease activity of these bacteria is likely to be important in colonisation of the host. Possession of glutamate dehydrogenase activity by both organisms suggests that one role of the urease may be to assimilate the available urea nitrogen. Modification of the local environment to facilitate long-term colonisation is another possible function. Protection from acid is unlikely to be a primary role as the natural habitat of the organism St1 is the non-acid-secreting tissue of the small intestine.
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PMID:The urease enzymes of Campylobacter pylori and a related bacterium. 317 69

A relatively rapid procedure is described for the isolation of the fourth component of complement (C4) from ovine plasma. The method, which recovers approximately 30% C4, is based upon DEAE Sephacel anion exchange chromatography of PEG precipitated plasminogen depleted plasma followed by cation exchange chromatography on CM Sepharose and finally gel filtration. SDS-PAGE of purified ovine C4 under reducing conditions revealed a complex pattern of bands which was interpreted on the basis of a three polypeptide chain structure for each of two distinct species, or isotypes, of C4 molecule herein termed C4A and C4B. Each isotype differs in the mol. wt of the alpha chain--108 and 95 K respectively. Nucleophilic substitution of immunoprecipitated ovine C4 with radiolabelled methylamine revealed that both C4 species contained a reactive thiol ester site and that each could be cleaved into an activated form (presumably C4b) characterised by a truncated alpha' chain some 8 K lower in mol. wt. A comparison of the isotype composition of purified C4 with that of immunoprecipitated C4 from the same animal indicated that the purification procedure favoured isolation of the C4B isotype. The mol. wts of both the alpha and beta chains were lowered following digestion of ovine C4 with neuraminidase.
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PMID:Purification and characterisation of ovine C4: evidence for two molecular forms in ovine plasma. 317 57

A myotoxin, bothropstoxin (BthTX), showing no detectable phospholipase A2 activity, was purified to homogeneity from the venom of the Brazilian snake Bothrops jararacussu by a combination of gel filtration on Sephadex G-75 and ion-exchange chromatography on SP-Sephadex C-25. Four phospholipases (Sm-SP1 to Sm-SPIV) were also isolated, the latter showing, similarly to BthTX (Sm-SPv) myonecrotic activity. Approximate mol. wts, as determined by SDS-PAGE, and pI of Sm-SPI to Sm-SPIV are: 22,400-4.2; 15,500-4.8; 13,800-6.9; and 13,200-7.7, respectively. BthTX is a single chain protein, approximate mol. wt 13,000, with 16 half-cystine residues, pI = 8.2 and LD50 = 7.5 mg/kg (i.p.) and 4.8 mg/kg (i.v.) for 20 g mice. The ten first N-terminal amino acid residues show a significant homology to other toxins with phospholipase structure. BthTX is specifically myotoxic, contrary to crude B. jararacussu venom which, although also myotoxic, affects intramuscular arteries and veins leading to thrombosis. BthTX and Sm-SPIV also differ from toxins isolated from the venom of other Brazilian snakes which are strongly hemorrhagic.
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PMID:Fractionation of Bothrops jararacussu snake venom: partial chemical characterization and biological activity of bothropstoxin. 317 51

Purified biotinidase (enriched 24,000-fold) from fresh human plasma exhibited reduced catalytic activity when incubated with heat-inactivated dialyzed plasma. The polypeptide fractions separated from the heat-inactivated dialyzed plasma using streptavidin-Sepharose resin showed the same effect on purified biotinidase. These inhibitory effects on biotinidase were partial (25-45%) rather than complete. The polypeptide fraction from streptavidin-Sepharose resin was analyzed by SDS-PAGE in the Laemmli system and by various types of HPLC. Analyses by ion-exchange and reversed-phase HPLC revealed the existence of three relatively small mol. wt polypeptides. Each of these peak fractions exhibited similar inhibitory effects on biotinidase activity. SDS-PAGE analysis indicated that the streptavidin affinity resin fraction was composed of four major polypeptides whose mol. wts were 120,000, 76,000, 53,000 and 27,000. The two bands of 120,000 and 76,000 corresponded to the mol. wts of the biotinyl subunit of pyruvate carboxylase, beta-methyl-crotonyl-CoA and/or propionyl-CoA carboxylase respectively. However, the polypeptides of mol. wts 53,000 and 27,000 were found to be two unique biotinyl-peptides present in human plasma. These bands on the gels were transblotted and exhibited a fluorescent activity after incubated with a FITC-avidin. These findings strongly suggest the existence of circulating plasma biotinyl-polypeptides as inhibitory factor(s) on human plasma biotinidase.
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PMID:Effect of plasma biotinyl-peptides on biotinidase activity. 325 55

Monoclonal antibody 5E2 identifies a new rabbit thymocyte specific cell surface molecule designated R-Ta. SDS-PAGE of molecules immunoprecipitated by 5E2 shows that R-Ta exists as a non-covalently associated hetero-dimer consisting of a light polypeptide chain (mol. wt approximately 12,000) and a bi-molecular species of a heavy chain (mol. wts of 45,000 and 40,000). The difference between the two forms of heavy chain can be attributed to different degrees of glycosylation. Each form of the R-Ta heavy chain has a polypeptide mol. wt of 34,000. At least three N-linked oligosaccharides and no significant O-linked sugars were found associated with R-Ta. Two dimensional electrophoresis of V8 protease peptide maps also indicate that the two forms of the heavy chains are similar, if not identical, in polypeptide primary structure. The light polypeptide was found to be serologically and structurally identical to beta-2-microglobulin. This was demonstrated in a previous study by reaction with goat anti-beta-2-microglobulin antisera. In this investigation the structural identity with beta-2-microglobulin was demonstrated by partial amino terminal sequence analysis. The partial amino acid sequence for 18 steps of the R-Ta heavy chain was also determined. A comparison of the amino acid sequence with other known sequences for the conventional Class I molecules of man, mouse and rabbit did not reveal any homology. Thus R-Ta is a new T-cell surface protein, and like human CD1, carries the unique distinction of thymocyte specificity, is beta-2-microglobulin associated, but is not Class I related.
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PMID:Biochemical properties of a novel rabbit thymocyte specific class I-like antigen. 326 85


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