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)

We have shown that aq. 100% (w/v) chloral hydrate (2,2,2-trichloroethane-1,1-diol) dissociates bovine heart cytochrome c oxidase. We have developed new procedures of polyacrylamide-gel electrophoresis in the presence of chloral hydrate that permit variation in the pH of the separation, and, by using these procedures, we have observed 15 components in preparations of the enzyme. This number contrasts with the eight bands that were seen on electrophoresis in the presence of SDS (sodium dodecyl sulphate) and urea. We have isolated material from these eight bands and have characterized each by electrophoresis in the presence of chloral hydrate. Twelve of the fifteen components that were seen by electrophoresis in chloral hydrate were identified as constituents of the eight bands seen by electrophoresis in the presence of SDS and urea. Two-dimensional electrophoretic separations confirmed these identifications ans showed that the other three components which were resolved as discrete bands by electrophoresis in the presence of chloral hydrate appeared to be diffusely present in the electrophoretic separations performed in the presence of SDS and urea, which suggested anomalous behaviour in that detergent. Trypsin treatment of cytochrome c oxidase caused total loss, as observed by electrophoretic separations in the presence of chloral hydrate, of a number of components. The trypsin-sensitive components included all of those that behaved anomalously in the presence of SDS and urea. Chloral hydrate is a potent non-ionic dissociating agent for cytochrome c oxidase and its use in polyacrylamide-gel electrophoresis, with variation in the pH of the gel, permits charge-dependent separations that should have general application in the analysis of membrane proteins.
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PMID:Additional components of bovine heart cytochrome c oxidase demonstrated by high-resolution polyacrylamide-gel electrophoresis in the presence of chloral hydrate. 627 32

The pathway of breakdown of membrane-bound benzodiazepine binding sites has been examined with proteolytic enzymes. Photoaffinity labeled benzodiazepine receptors were degraded for varying amounts of time and at varying enzyme concentrations. The properties of fractions both remaining in the membrane and released into the supernatant were examined for their apparent molecular weight by SDS gel electrophoresis. Trypsin treatment converted the 46K subunits of the GABA/BDZ complex which bind 3H-flunitrazepam into 40K and 27.5K fragments which remained in the membrane and finally a small fragment which was released into the supernatant. An endogenous trypsin-like activity in the membrane fractions has similar proteolytic effects on the membrane bound receptor.
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PMID:Proteolytic degradation of neuronal benzodiazepine binding sites. 631 38

The role played by the gut juice of insects in the infective process of insect viruses was examined. Analysis of larval gut extract of Heliothis armigera by SDS-PAGE revealed protease activity associated with components of molecular weights 48,000 and 94,000. Proteases were found to be associated with occlusion bodies and virions of both nuclear polyhedrosis virus (NPV) and cytoplasmic polyhedrosis virus (CPV) infecting H. armigera. CPV occlusion bodies were dissolved by gut juice extract at pH 8.0, trypsin and chymotrypsin at pH 8.0, and carbonate-chloride solution at pH 10.5. Trypsin treatment was selective for occlusion bodies of CPV at pH 8.0, whereas solutions more alkaline than pH 10.0 without added enzymes were adequate to digest NPV occlusion bodies. This property was used to identify and separate the two types of viruses from a mixed infection. Gut extract proteases have characteristics similar to those of trypsin.
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PMID:Midgut and viral associated proteases of Heliothis armigera. 633 72

Plasmin, generated by the interaction of urokinase with plasminogen, degraded the apoprotein B moiety of human low density lipoprotein to yield distinct high moleculr weight intermediates under conditions where only a small fraction (less than 3%) of the protein was hydrolyzed to trichloroacetic acid-soluble products. The molecular weights of these intermediates were between 60 000 and 200 000 as estimated by SDS-polyacrylamide electrophoresis. Trypsin treatment yielded fragments of similar size to those obtained with plasmin. When enzyme-treated low density lipoproteins were added to bovine aortic smooth muscle cells in culture, the receptor-binding, and rates of internalization and degradation were no different from those obtained in the case of native low density lipoproteins.
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PMID:Plasmin-treated low density lipoproteins: polypeptide analyses and metabolism by cultured smooth muscle cells. 645 2

Membrane fusion in vitro between Golgi apparatus- and plasma-membrane-rich fractions isolated from maize (Zea mays) roots was found to be dependent on Ca2+ and the membrane proteins. Trypsin treatment of mixed membrane fractions before the addition of Ca2+ inhibited their ability to fuse. It resulted also in a selective and progressive elimination of a characteristic intense polypeptide band (B1) on gel electrophoresis. This polypeptide was not removed by chymotrypsin or thermolysin. B1 is an integral membrane protein with an exposed portion to the outside. Sodium deoxycholate was used to solubilize the proteins of mixed membrane fractions. Extracted proteins analysed by non-SDS (sodium dodecyl sulphate) polyacrylamide-gel electrophoresis revealed the presence of four isolated bands. When re-electrophoresed in the presence of SDS, one of these bands exhibited the same mobility as polypeptide B1. Enzymic staining of non-SDS-polyacrylamide gels showed that this protein has Ca2+- and Mg2+-dependent ATPase activity. Its possible role in membrane fusion is discussed.
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PMID:The extraction from maize (Zea mays) root cells of membrane-bound protein with Ca2+-dependent ATPase activity and its possible role in membrane fusion in vitro. 645 76

Monoclonal antibodies (McAb) against human ejaculated sperm were developed from mice immunized with sperm membrane preparations. A solid-phase radioimmunoassay, with dried sperm as antigen, was employed in McAb screening. The tissue and species specificity of monoclonal antibodies HS 2, 4 and 6 were evaluated after absorption of antibody preparations with heterologous sperm, human serum or seminal plasma or cells from other human organs. The sensitivity of HS 2, 4 and 6 antigens to trypsin exposure was determined: HS 4 antigen was highly sensitive while HS 2 and 6 were not. The regional distribution of McAb 4 on intact sperm cells was determined by immunofluorescence staining. HS 4 may be a sperm-coating antigen based on its presence on sperm and in seminal plasma. This possibility led to an investigation of its role in sperm capacitation. HS 4 antibody binding was reduced when capacitated sperm were compared with noncapacitated cells. HS 4 antibody, when present during capacitation and insemination, was without effect on sperm motility or fusion with zona-free hamster eggs. Trypsin removal of as much as 60% of HS 4 antigen from the cell population also did not impact on sperm function. To identify the molecular correlate of HS 4 antigen, membrane components were extracted from washed sperm with Nonidet P-40, concentrated by acetone precipitation and analyzed electrophoretically in SDS-urea on 10% polyacrylamide slab gels. Immunoassays on protein blots with peroxidase-coupled second antibody identified a single reactive species in the molecular weight range of 130,000. Multiple reactive components were detected in blot transfers of seminal plasma.
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PMID:Characterization of human sperm surface antigens with monoclonal antibodies. 662 50

Bacteriophage T4 wild-type is not sensitive to heating at 60 degrees C. Trypsin at this temperature quickly inactivates the bacteriophage, with first-order kinetics for about the first 60 min. The half-inactivation period is around 15 min. The characteristics of this inactivation reaction have been studied. Inactivation of T4 particles is paralleled by a loss in ability to adsorb to bacteria. SDS-PAGE reveals a 'clipping' of gp 37, the protein of the distal part of the long tail fibres, during the inactivation reaction. gp 37 is the only protein to be modified under these conditions. Mutants have been isolated which resist this modification, they map in gene 37.
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PMID:The tail fibre of bacteriophage T4 is sensitive to proteases at elevated temperatures. 663 11

Protease digestion of acetylcholine receptor-rich membranes derived from Torpedo californica electroplaques by homogenization and isopycnic centrifugation results in degradation of all receptor subunits without any significant effect on the appearance in electron micrographs, the toxin binding ability, or the sedimentation value of the receptor molecule. Such treatment does produce dramatic changes in the morphology of the normally 0.5- to 2-microns-diameter spherical vesicles when observed by either negative-stain or freeze-fracture electron microscopy. Removal of peripheral, apparently nonreceptor polypeptides by alkali stripping (Neubig et al. 1979, Proc. Natl. Acad. Sci. U. S. A. 76:690-694) results in increased sensitivity of the acetylcholine receptor membranes to the protease trypsin as indicated by SDS gel electrophoretic patterns and by the extent of morphologic change observed in vesicle structure. Trypsin digestion of alkali-stripped receptor membranes results in a limit degradation pattern of all four receptor subunits, whereupon all the vesicles undergo the morphological transformation to minivesicles. The protein-induced morphological transformation and the limit digestion pattern of receptor membranes are unaffected by whether the membranes are prepared so as to preserve the receptor as a disulfide bridged dimer, or prepared so as to generate monomeric receptor.
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PMID:Protease effects on the structure of acetylcholine receptor membranes from Torpedo californica. 699 98

Developing pea (Pisum sativum L.) cotyledons were labeled with radioactive amino acids, glucosamine, and mannose in pulse an pulse-chase experiments to study the synthesis, glycosylation, and transport of the reserve proteins vicilin and legumin to the protein bodies. Tissue extracts were fractionated on sucrose gradients to isolate either the endoplasmic reticulum (ER) or the protein bodies. Immunoaffinity gels were used to determine radioactivity in the reserve proteins (legumin and vicilin). After pulse-labeling for 45 min with amino acids, about half the total incorporated radioactivity coincided closely with the position of the ER marker enzyme NADH-cytochrome c reductase at a density of 1.13 g . cm-3 on the sucrose gradient. Both radioactivity and enzyme activity shifted to a density of 1.18 g . cm-3 in the presence of 3 mM MgCl2 indicating that the radioactive proteins were associated with the rough ER. Approximately half of the incorporated radioactivity associated with the rough ER was in newly synthesized reserve protein and this accounted for 80% of the reserve protein synthesized in 45 min. Trypsin digestion experiments indicated that these proteins were sequestered within the ER. In pulse-chase experiments, the reserve proteins in the ER became radioactive without appreciable lag and radioactivity chased out of the ER with a half-life of 90 min. Radioactive reserve proteins became associated with a protein body-rich fraction 20-30 min after their synthesis and sequestration by the ER. Pulse-chase experiments with radioactive glucosamine and mannose in the presence and absence of tunicamycin indicated that glycosylation of vicilin occurs in the ER. However, glycosylation is not a prerequisite for transport of vicilin from ER to protein bodies. Examination of the reserve protein polypeptides by SDS PAGE followed by fluorography showed that isolated ER contained legumin precursors (Mr 60,000-65,000) but not the polypeptides present in mature legumin (Mr 40,000 and 19,000) as well as the higher molecular weight polypeptides of vicilin (Mr 75,000, 70,000, 50,000, and 49,000). The smaller polypeptides of vicilin present in vicilin extracted from protein bodies (Mr 12,000-34,000) were absent from the ER. The results show that newly synthesized reserve proteins are preferentially and transiently sequestered within the ER before they move to the protein bodies, and that the ER is the site of storage protein glycosylation.
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PMID:Role of the endoplasmic reticulum in the synthesis of reserve proteins and the kinetics of their transport to protein bodies in developing pea cotyledons. 706 59

Trypsin inhibitors were isolated from wheat endosperm, and a major inhibitor (wheat endosperm trypsin inhibitor-I, WETI-I) was purified by ion-exchange chromatographies on CM-Sephadex and SP-Sephadex, gel filtration on Sephadex G-75 and chromatofocusing on Polybuffer exchanger PBE 94. This inhibitor was a polypeptide composed solely of amino acids, and its pI value was 9.35. It was found to be homogeneous in gel electrophoresis and velocity sedimentation. It showed strong inhibition on bovine trypsin but weak inhibition on bovine alpha-chymotrypsin. The molecular weight of the inhibitor was approximately 7,800 as judged from SDS-gel electrophoresis. This finding, along with the trypsin inhibition data, suggested that the inhibitor bound trypsin in the molar ratio of 1:1. Certain other properties of the inhibitor, including amino acid composition and UV spectral characteristics are presented.
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PMID:Isolation and partial characterization of a trypsin inhibitor from wheat endosperm. 717 81


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