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)

Protein G is a streptococcal cell wall protein with separate and repetitively arranged binding domains for immunoglobulin G (IgG) and human serum albumin (HSA). In this work, the binding of protein G to HSA was studied. The results suggest that a single binding site is present on HSA: the apparent size of the HSA-protein G complex (230 kDa) corresponded to two or three HSA molecules bound to one protein G molecule, and Ouchterlony immunodiffusion did not yield any precipitate between protein G and HSA. HSA was cleaved by pepsin and CNBr into several fragments which were identified by SDS-PAGE and N-terminal amino acid sequencing, and the binding of protein G to the fragments was studied in Western blot experiments. The results indicated that the binding area was located in disulfide loops 6-8, involving both the second (loop 6) and the third (loops 7 and 8) domain of HSA. One of the protein G binding pepsin fragments, with an apparent molecular mass of 5.5 kDa, located in loops 7 and 8, was isolated and found to completely inhibit the binding between protein G and the intact HSA, again suggesting a single protein G binding site on serum albumin. Reducing the disulfide bonds of HSA, and subsequent alkylation of the half-cystine residues, significantly decreased the affinity for protein G. Protein G bound to albumin from baboon, cat, guinea pig, hamster, hen, horse, man, mouse, and rat, but not to albumin from cow, dog, goat, pig, rabbit, sheep, snake, or turkey.
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PMID:Localization of the binding site for streptococcal protein G on human serum albumin. Identification of a 5.5-kilodalton protein G binding albumin fragment. 173 3

A cysteine protease (trypanopain-Tc) with cathepsin-L-like properties has been purified from Trypanosoma congolense. The enzyme has an apparent molecular mass of 31-32 kDa by SDS/PAGE and 66 kDa by gel chromatography. It has a pI 7.4 and a high affinity for concanavalin A. Trypanopain-Tc catalyses the limited proteolysis of a variety of protein substrates such as fibrinogen, serum albumin and trypanosome variant-surface glycoprotein. It has minimal or no activity against casein or elastin. A variety of peptidyl amidomethylcoumarins and peptidyl diazomethanes were used to test the specificity of trypanopain-Tc. The better substrates had Arg or Lys in P1 and hydrophobic amino acids in P2 and P3. The best substrate found for trypanopain-Tc was Z-Phe-Arg-NHMec (Z, benzyloxycarbonyl; NHMec, 7-amido-4-methylcoumarin). The kinetic constants for the hydrolysis of Z-Phe-Arg-NHMec were kcat = 17.4 s-1, Km = 4.4 microM, kcat/Km = 4.0 microM-1.s-1, which are very similar to those of cathepsin L with this substrate. The specific substrates for cathepsin B (Z-Arg-Arg-NHMec) and cathepsin H (Arg-NHMec) were not hydrolysed by trypanopain-Tc under the conditions tested. The pH optimum of trypanopain-Tc against Z-Phe-Arg-NHMec was pH 6.0 but it showed a broad peak of activity extending well into the alkaline region. The enzyme was activated by low-molecular-mass thiol compounds and inhibited by cystatin, L-trans-epoxysuccinyl-4-guanidinobutane (E-64) and a variety of peptidyl diazomethanes. The most effective diazomethane inhibitors (Z-Leu-Leu-Met-CHN2, Z-Leu-Met-CHN2 and Z-Leu-Lys-CHN2, were inhibitory at nanomolar concentrations and were trypanocidal in vitro after 24-48 h incubation in greater than or equal to 20 microM [inhibitor]. However, it is not clear whether the trypanocidal activity of these inhibitors is a consequence of the inhibition of trypanopains or of some other essential proteolytic activities within the parasites.
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PMID:Characterisation of a cysteine protease from bloodstream forms of Trypanosoma congolense. 174 Jan 49

A new protein, called alboaggregin-B (AL-B), has been isolated from Trimeresurus albolabris venom by ion-exchange chromatography. It agglutinated platelets without the need for Ca2+ or any other cofactor. The purified protein showed an apparent molecular mass on SDS-PAGE and gel filtration of about 23 kDa under nonreducing conditions. Ristocetin did not alter the binding of AL-B to platelets or affect AL-B-induced platelet agglutination. Agglutinating activity was not dependent on either proteolytic or lectin-like activity in AL-B. Binding analysis showed that AL-B bound to platelets with high affinity (Kd = 13.6 +/- 9.3 nM) at approximately 30,800 +/- 14,300 binding sites per platelet. AL-B inhibited the binding of labeled bovine von Willebrand factor (vWF) to platelets. Monoclonal antibodies against the 45-kDa N-terminal domain of platelet glycoprotein Ib inhibited the binding both of AL-B and of bovine vWF to platelets, and also inhibited platelet agglutination induced by AL-B and bovine vWF. Specific removal of the N-terminal domain of GPIb by treatment of the platelets with elastase or Serratia marcescens protease reduced the binding of labeled AL-B and bovine vWF to platelets and blocked platelet agglutination caused by both agonists. Monoclonal antibodies to glycoprotein IIb/IIIa, to bovine vWF, and to bovine serum albumin did not show any effect on the binding of AL-B to platelets. Our results indicate that the binding domain for AL-B on platelet GPIb is close to or identical with the one for vWF. This new protein may be a very useful tool for studying the interaction between platelets and vWF.
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PMID:Alboaggregin-B: a new platelet agonist that binds to platelet membrane glycoprotein Ib. 174 71

Crosslinking of collagenous biomaterials currently employs the use of glutaraldehyde. The putative enhancement of glutaraldehyde crosslinking by lysine was investigated in three model systems: bovine pericardium, collagen membranes, and bovine serum albumin. Repetitive sequential treatment of bovine pericardium with glutaraldehyde and lysine and finally with formaldehyde produced a matrix which, by the two criteria used (shrinkage temperature and urea/SDS soluble collagen), was shown to be more highly crosslinked than pericardium fixed in glutaraldehyde alone. Essentially the same results were obtained when membranes prepared from pepsin-soluble pericardial collagen were subjected to sequential glutaraldehyde and lysine treatments, reaching shrinkage temperatures of more than 90 degrees C. Heart valves prepared from lysine-enhanced glutaraldehyde crosslinked bovine pericardium were tested in vitro in an accelerated fatigue tester and have been shown to behave satisfactorily after 300 million cycles. These additional crosslinks proved to be stable in saline at 37 degrees C. Studies on bovine serum albumin attempted to get an insight into the mechanisms of lysine enhancement of glutaraldehyde crosslinking by treating sequentially albumin with glutaraldehyde and lysine and analysis of the products by gel filtration and SDS-PAGE. These studies suggest that free amino groups exposed by proteins are initially reacted with glutaraldehyde and then bridged by the diamino compound (lysine) producing more extensive intermolecular crosslinking than glutaraldehyde alone.
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PMID:Lysine-enhanced glutaraldehyde crosslinking of collagenous biomaterials. 179 97

Dialysates from Dermatophagoides farinae were partially purified. Fractionation on HPLC and anion exchange chromatography revealed that the dialysates consisted of 5 major fractions of glycoprotein whose apparent molecular sizes were 5.1, 4.1, 3.2, and less than 1.35 kD on HPLC. The apparent molecular size of two fractions was 5.3 and 2.9 kD on SDS-PAGE. They were basic glycoproteins which had a pI ranging from 7.46 to 8.71 on PAG-IEF. These fractions were allergenic in the RAST and ELISA inhibition tests but not in the skin prick test (SPT). Our results suggest that the dialysates from D. farinae have haptenic properties. The dialysates from D. farinae (low molecular weight) and its 5 fractions bound noncovalently to human serum albumin (HSA) at the free tyrosine residues of HSA. They proved to bind noncovalently to serum proteins and collagens. Once they bound to proteins, the conjugates became allergenic not only in the RAST and ELISA inhibition test but also in the SPT. Our results provide evidence that the dialysates from D. farinae have haptenic properties.
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PMID:Studies of dialysates from Dermatophagoides farinae: partial purification and haptenic properties of dialysates from Dermatophagoides farinae. 180 89

An extracellular proteinase from Enterococcus faecalis subsp. liquefaciens has been purified 780-fold by a method including gel filtration on Sephadex G-50 and affinity chromatography with gramicidin J as ligand. Approximately 15% of the original enzyme activity was recovered. A purification of 14,800-fold, with 11.4% yield, may be reached using chromatofocusing as final step in the purification procedure. The molar mass of the enzyme has been estimated to be approximately 30 kDa by Sephadex gel filtration and approximately 26 kDa by SDS-PAGE. The isoelectric point has been found to be 4.6. Maximum enzyme activity of the proteinase has been observed at pH 7.5 and 45 degrees C. The enzyme hydrolyzed bovine serum albumin, alpha-lactoalbumin, beta-lactoglobulin, casein and pork myofibrillar and sarcoplasmic proteins. The extracellular proteinase was very stable; the enzyme maintained its activity in cell-free extracts over a very wide range of temperatures (-25 to 37 degrees C) for at least 2 months. At 12 degrees C, it was stable in the pH range of 5.5 to 8.0.
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PMID:Extracellular proteinase from Enterococcus faecalis subsp. liquefaciens. II. Partial purification and some technological important properties. 182 67

An antiserum, elicited by a synthetic peptide coupled to bovine serum albumin, reacted specifically with the non-structural 16K protein of tobacco rattle virus. The protein was detected in extracts of systemically infected Nicotiana clevelandii leaves, but only in those made with the aid of SDS, urea and 2-mercaptoethanol. Immunogold labelling of ultrathin sections showed that the protein was mainly associated with nuclei, but was also present in the cytoplasm. These observations suggest that the 16K protein binds to macromolecular components of infected cells, especially in nuclei, but do not clarify its function.
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PMID:Nuclear location of the 16K non-structural protein of tobacco rattle virus. 183 93

Cementum occupies a unique anatomical location where soft connective tissues of the periodontium are attached to root surfaces. Cell attachment properties of proteins present in cementum were studied. Human and bovine cementum were extracted with 0.5 mol/L CH3COOH followed by 4 mol/L guanidine, and proteins were separated by ion-exchange chromatography and SDS-polyacrylamide gel electrophoresis. Cells were labeled with radioactive amino acids and added to tissue-culture plastic plates incubated with cementum proteins, and attachment was measured. Results showed that cementum proteins promoted the attachment of smooth muscle cells, endothelial cells, and fibroblasts, but not epithelial cells. Fibroblasts attached more efficiently than other cell types, and they manifested spreading with re-organization of actin filaments. No attachment occurred to plates incubated with endotoxin from A. actinomycetemcomitans. Fewer fibroblasts attached to plates treated with cementum proteins in the presence of endotoxin, but cells pre-treated with endotoxin attached normally. Attachment was not inhibited when plates were incubated first with attachment proteins and then with endotoxin; however, it was decreased when endotoxin or bovine serum albumin preceded cementum proteins. Cementum proteins with Mr 68,000, 61,000, 55,000, and 36,000 (p68, p61, p55, and p36, respectively) manifested attachment activity, while protein(s) with Mr 23,000-24,000 did not. Western blots revealed that guanidine extracts contained three bands cross-reacting with anti-bovine sialoprotein-II antibody, but the p61, p55, and p36 were negative. We conclude that cementum contains bovine sialoprotein-II and at least four other fibroblast attachment proteins, and that they do not support epithelial cell attachment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cell attachment activity of cementum proteins and mechanism of endotoxin inhibition. 183 26

In an attempt to raise specific anti-GAP-43 antibodies, a C-terminal tetradecapeptide was synthesized based on the predicted rat GAP-43 amino acid sequence using the F-moc polyamide solid phase procedure. The synthesized carboxy-terminal peptide was purified by reverse phase HPLC, conjugated to bovine serum albumin (BSA) and used as an immunogen. Polyclonal antipeptide antibodies raised in rabbits were affinity purified and their specificity for GAP-43 tested by Western blotting. Brain and spinal cord homogenates and GAP-43 enriched synaptosomal membrane fractions were analysed either by SDS-PAGE or reverse phase HPLC. The anti-GAP-43 antibodies detected a major immunoreactive band at 43 kDa (B-50), and a minor immunoreactive band at 38 kDa (B-60) together with an additional protein-band at 68 kDa, which was related to the peptide carrier, BSA. Immunohistochemical studies using these carboxy-terminal antipeptide antibodies revealed a widespread distribution of GAP-43 immunoreactivity throughout the adult rat brain and spinal cord, in a pattern generally consistent with earlier histochemical studies. It is concluded that the C-terminal GAP-43 specific tetradecapeptide is a potent immunogen and provides a convenient tool for the production of sequence specific anti-GAP-43 antibodies.
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PMID:Production and characterization of an anti-peptide antibody specific for the growth-associated protein, GAP-43. 183 4

Human cholesterol gallstones contain a pigmented organic matrix that may originate from biliary sludge. The cholesterol gallstone matrix contains mucin, bile pigments, and calcium salts. The goal of this study was to examine whether non-mucin proteins are present in the matrix of cholesterol gallstones. Matrix was prepared from cholesterol gallstones from 18 patients. Proteins were identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and by molecular sieve high-performance liquid chromatography (HPLC). Two proteins were present in each gallstone and migrated with or just adjacent to standards of bovine serum albumin on SDS-PAGE. Several additional lower molecular weight proteins were identified, but not in every gallstone. Protein fractions contained visible pigment after chloroform extraction, and pigment co-eluted with proteins on HPLC, suggesting binding of pigments to proteins in the matrix. We conclude that low molecular weight proteins are present in the cholesterol gallstone matrix. The major protein appears to be serum albumin, although definitive identification has not been established. The origin of these matrix proteins and their possible significance in the pathogenesis of cholesterol cholelithiasis is unknown.
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PMID:Non-mucin proteins in the matrix of human cholesterol gallstones. 189 14


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