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

The sarcoplasmic reticulum (SR) of rabbit skeletal muscle was irradiated with ultraviolet light (UV) in the presence of vanadate plus 2 mM EGTA, 10 mM MgCl2, 20% DMSO, and 50 mM PIPES (pH 6.5) at room temperature. In the presence of 100 microM vanadate, the Ca(2+)-uptake activity of SR rapidly decreased and was almost lost in 20 min. The activity was inhibited as a function of vanadate concentration with an apparent Ki of about 20 microM. On the other hand, Ca(2+)-dependent ATP hydrolytic activity as well as phosphoenzyme (EP) formation activity decreased very slowly, and more than 50% of these activities remained 20 min after initiation of the vanadate-UV treatment. Half inhibition of these activities required about 100 microM vanadate. The loss of the relationship between Ca(2+)-uptake and ATPase reaction was found to be mainly caused by an increase in the Ca2+ permeability of the SR membrane, which was raised by increasing the vanadate concentration or UV irradiation time in a manner similar to that observed for the Ca2+ uptake. No rise in Ca2+ permeability occurred in liposomes reconstituted from SR lipid when they were irradiated with UV in the presence of 100 microM vanadate. When the vanadate-UV-treated SR was allowed to react with fluoral-P (4-amino-3-penten-2-one), an indicator of aldehyde, and the membrane proteins were separated by HPLC in the presence of SDS, the fluorescent probe was found to be closely associated with the Ca(2+)-ATPase fraction.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Irradiation with ultraviolet light in the presence of vanadate increases Ca2+ permeability of the sarcoplasmic reticulum membrane via Ca(2+)-ATPase. 760 20

The sperm acrosome is a regulated secretory granule that undergoes exocytosis during fertilization. To elucidate the structural organization of the contents within the acrosome, guinea pig sperm acrosomal apical segments were isolated and mapped by two-dimensional polyacrylamide gel electrophoresis (PAGE). Although complex, the two-dimensional PAGE map was dominated by two M(r) 50,000 polypeptides (p50 and proacrosin), a M(r) 67,000 polypeptide (p67), and a M(r) 32,000 polypeptide (sp32). Proacrosin (pI > 8.0), p67, and sp32 were extracted from apical segments by 1 M NaCl. Protein p50, a relatively acidic polypeptide, was not extracted in 1 M NaCl and/or 1% Triton X-100 at 4 degrees C, but was solubilized with 6 M urea. Protein p50 was purified from the urea extract by elution from DEAE-Sephacel with 100 mM guanidine HCl and appeared homogeneous by SDS-PAGE. Antibodies to p50 were monospecific as judged by Western blot analysis. Indirect immunofluorescence indicated that p50 was restricted to the acrosomal apical segment. Incubation of apical segments at pH 7.5 in the presence of 1 mM EDTA at 37 degrees C resulted in the release of p50 into the 200,000 x g supernatant fluid, a process that was reversed by a subsequent incubation with 1.5 mM CaCl2, but not with MgCl2. The Ca(2+)-dependent reassociation of p50 with the acrosomal apical segments was reversed by the addition of 2.0 mM EGTA, indicating that p50 binding is dependent on free Ca2+ concentrations. When acrosomal matrices were purified following Triton X-100 extraction, p50 was the major component, with p67, proacrosin, and sp32 as less prominent constituents. Molecular cloning demonstrated that p50 is a unique, testis-specific member of the pentaxin family of calcium-dependent binding proteins.
 ...
PMID:The sperm acrosomal matrix contains a novel member of the pentaxin family of calcium-dependent binding proteins. 779 65

In order to evaluate the effect of chaotropic agents on proteoglycan and non-collagenous proteins, chicken xiphoid cartilage was treated with guanidine-HCl and MgCl2 in different concentrations (1M to 5M), and different periods of time (12, 24, 48 and 72 hr). The maximum yield of uronic acid was obtained with 3M MgCl2 (73.3%). Concentrations of 4M and 5M of MgCl2 showed that much less uronic acid was removed, 55.3% and 38.1% respectively. Extraction with 3M MgCl2 and 3M guanidine-HCl resulted better efficiency when performed for 48 hr. Analysis by SDS-PAGE of the extracts obtained with guanidine-HCl and MgCl2 in different concentrations pointed out that most components are equally removed with the two solvents, showing that the extraction with MgCl2 is an alternative assay to remove non-collagenous proteins from extracellular matrix.
 ...
PMID:Effect of magnesium chloride and guanidinium chloride on the extraction of components of extracellular matrix from chicken cartilage. 782 26

Escherichia coli cardiolipin synthase catalyzes the conversion of two phosphatidylglycerol molecules to cardiolipin and glycerol. This enzyme was amplified in strain BL21(DE3) bearing recombinant plasmid pLR3, which was itself constructed by inserting the cls gene downstream from a T7 RNA promoter. Membranes from BL21(DE3)/pLR3 have over 1200 times more cardiolipin synthase activity than do comparable membranes from wild type cells. The enzyme was purified to homogeneity by extraction with Triton X-114 and chromatography on DEAE-cellulose. The purified enzyme migrated as a single band (46 kDa) on SDS-PAGE. This, along with SDS-PAGE analysis of induced protein, supports the notion that cls is the structural gene for cardiolipin synthase. Cardiolipin synthase activity was determined in a mixed micelle assay in which phosphatidyl[2-3H]glycerol was the substrate. The enzyme is inhibited by the product of the reaction, cardiolipin, and by phosphatidate. However, it is not inhibited by two other anionic phosphoglycerides, phosphatidylinositol and bis-phosphatidate. Phosphatidylethanolamine partially offsets inhibition by cardiolipin but not by phosphatidate. Magnesium chloride has the opposite effect. Cardiolipin inhibition of cardiolipin synthase probably plays an important role in regulating cardiolipin synthesis in E. coli.
 ...
PMID:The effects of phosphoglycerides on Escherichia coli cardiolipin synthase. 791 16

Mouse plasma platelet-activating factor acetylhydrolase (PAF-AH) has an apparent Km of 7.4 microM and a Vmax of 21.6 nmol/min per mg protein. Comparison with values reported for the human and the rat enzymes shows at least a 5-fold higher Vmax and similar enzyme-substrate affinity. Although lecithin:cholesterol acyltransferase (LCAT) and one component of the PAF-AH share similar masses and lipoprotein association, they are distinct enzymes. Similarly, PAF-AH is distinct from the phospholipase A2 (PLA2) and the lysophospholipase of mouse plasma. A series of PAF structural analogs showed either competitive inhibition or a mixed type of inhibition of PAF-AH. Mouse plasma PAF-AH is highly sensitive to 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) and is activated by deoxycholate. SDS-PAGE showed that two distinct proteins with molecular masses of 46 and 63 kDa contribute to the PAF-AH activity. The HDL-VHDL lipoprotein associated PAF-AH is precipitated to an extent of about 60% by phosphotungstate-MgCl2 and Tween 20 only partially solubilises the precipitated enzyme under conditions which can precipitate and solubilise the human enzyme.
 ...
PMID:The mouse plasma PAF acetylhydrolase: I. Characterization and properties. 792 89

Methods were developed for the purification, at high yield, of four different particle types of African horsesickness virus serotype 9 (AHSV-9). These products included virus particles purified on CsCl gradients which contain proteins apparently directly comparable to those of bluetongue virus (VP1 to VP7); virus particles purified on sucrose gradients which also contain, as a variable component, protein NS2; infectious subviral particles (ISVPs), containing chymotrypsin cleavage products of VP2; and cores, obtained by treating purified ISVPs with 1 M-MgCl2 to remove the components of the outer capsid layer (VP5 and VP2 cleavage products). Additional protein bands migrating with apparent M(r)s lower than that of VP5 were detected during SDS-PAGE analysis of virus particles. These appear to be conformational variants of VP5 and are identified as VP5' and VP5". BHK-21 cells infected with this strain of AHSV-9 produce large quantities of flat, usually hexagonal crystals of VP7, a major group antigen and core protein; these were also purified. Either 20 mg of virus particles, 20 mg of ISVPs or 10 mg of cores as well as 20 mg of VP7 crystals could be purified from approximately 8 x 10(9) infected cells. None of the preparations of particles or crystals showed any detectable contamination with BHK-21 cell proteins or antigens, as determined by SDS-PAGE or indirect ELISA. Virus particle and ISVP preparations had similar specific infectivities for BHK-21 cells (approximately 1 x 10(9) TCID50/A260 unit) but the infectivity of cores was approximately 10(5)-fold lower.
 ...
PMID:Purification and properties of virus particles, infectious subviral particles, cores and VP7 crystals of African horsesickness virus serotype 9. 804 87

Plant clathrin-coated vesicles (CCV), suitably protected against proteolysis, were isolated from zucchini hypocotyls, and screened for the presence of adaptin-like polypeptides using monoclonal antibodies prepared against alpha, beta(beta') and gamma-adaptins of bovine brain. An immunoreactive polypeptide in plant CCV was only detected in the case of the beta(beta')-adaptin antibody. This polypeptide has a molecular mass of 108 kDa in SDS-PAGE, and gives rise to a major cleavage product of 70 kDa after proteolysis with trypsin. Gel filtration of 0.75 M MgCl2-dissociated coat proteins showed that the plant beta(beta')-type adaptin eluted with other polypeptides in a manner similar to the adaptor complexes of brain CCV. Upon subsequent hydroxyapatite chromatography the immunoreactive polypeptide eluted in fractions corresponding to Golgi (HA-I) rather than plasma membrane (HA-II) brain adaptor complexes. In addition, this polypeptide did not shift to a higher molecular mass when subjected to urea-SDS-PAGE. Confirmation of the presence of a beta-type adaptin in plants was provided by dot and Southern blotting experiments using genomic DNA from zucchini hypocotyls and a beta-adaptin cDNA clone from human fibroblasts.
 ...
PMID:Identification of a beta-type adaptin in plant clathrin-coated vesicles. 805 48

Endonuclease VIII, a novel presumptive DNA repair enzyme, was isolated from Escherichia coli by FPLC1 purification. The enzyme was found in strains that contained or lacked endonuclease III and was purified by radial flow S-Sepharose, Mono S, phenyl-Superose, and Superose 12 FPLC. Examination of the properties of endonuclease VIII showed it to have many similarities to endonuclease III. DNA containing thymine glycol, dihydrothymine, beta-ureidoisobutyric acid, urea residues, or AP sites was incised by the enzyme; however, DNA containing reduced AP sites was not. HPLC analysis of the products formed by exhaustive enzymatic digestion of damage-containing DNA showed that endonuclease VIII released thymine glycol and dihydrothymine as free bases. Taken together, these data suggest that endonuclease VIII contains both N-glycosylase and AP lyase activities. Consistent with this idea, DNA containing AP sites or thymine glycols, that was enzymatically nicked by endonuclease VIII was not a good substrate for E. coli DNA polymerase I, suggesting that endonuclease VIII nicks damage-containing DNA on the 3' side of the lesion. Also, since monophosphates were not released after treating thymine glycol-containing DNA with endonuclease VIII, the enzyme does not appear to have exonuclease activity. The enzyme activity was maximal in 75 mM NaCl or 5 mM MgCl2. Analysis of endonuclease VIII by both Superose FPLC and Sephadex yielded native molecular masses of 28,000 and 30,000 Da, respectively. SDS-PAGE, in conjunction with activity gel analysis, gave a molecular mass of about 29,000 Da. Furthermore, renaturation of the putative active band from SDS-PAGE gave rise to an active enzyme.
 ...
PMID:Isolation and characterization of endonuclease VIII from Escherichia coli. 811 Jul 59

Peripheral blood eosinophils from normal subjects and patients with atopic dermatitis were isolated on a Percoll gradient and incubated with [gamma 32P] ATP in the presence of Mg2+. After the reaction was stopped, SDS/PAGE was performed and autoradiography was used to determine the incorporation of 32P into the proteins in the eosinophils. Both normodense and hypodense eosinophils showed 32P incorporation into the proteins at the molecular weights of 65 kDa & 66.2 kDa. These reactions were dependent upon Mg2+ concentration, and maximal response was observed at concentrations of 2-6 mM MgCl2. 32P incorporation into the bands was dependent upon the reaction time and temperature, and maximal response was observed at 20 degrees C. 32P incorporation into the proteins was inhibited by Ca2+ in a dose-dependent manner. Cyclic GMP at concentrations of 5 x 10(-8) to 5 x 10(-6) M enhanced the 32P incorporation. These data suggest the possible presence of protein kinase in human peripheral blood eosinophils.
 ...
PMID:[Possible presence of protein kinase in human peripheral blood eosinophils]. 825 Jul 35

Subunit III, the 8 kDa component of the chloroplast CFo H+ channel, was isolated and purified from pea thylakoids for the purpose of studying its Ca(2+)-binding properties. After n-butanol extraction and ether precipitation, HPLC purification was accomplished using a poly(styrene-divinylbenzene) column which removes lipid and protein contaminations. The main components of protein contamination were two hydrophobic proteins of near 4 kDa molecular mass, the psaI and psbK gene products associated with PSI and PSII reaction centers, respectively. Purified subunit III as well as the unfractionated organic-solvent soluble preparation were used in a 45Ca(2+)-ligand blot assay known to detect high affinity Ca(2+)-binding sites in proteins. Polypeptides were separated with SDS-PAGE and were transferred onto PVDF membranes. Treatment of the membrane with 45CaCl2 in the presence of 10-fold excess of MgCl2 and 200-fold excess KCl led to the labeling of only the 8 kDa polypeptide. The Ca2+ binding was inhibited after derivatizing aqueously exposed carboxyl groups with a water soluble carbodiimide plus a nucleophile, after de-formylation of the N-terminal methionine, or with a subsequent treatment with La3+. Ca2+ binding was maximum at pH 7.5-8.5 and was greatly decreased at acidic pH. Dicyclohexylcarbodiimide treatment (no nucleophile was added) of thylakoid membranes, which derivatizes the hydrophobically located Glu-61, decreased the electrophoretical mobility of isolated subunit III but did not inhibit the Ca2+ binding. The data indicate that the carbonyl group of the formylated N-terminal Met-1 and probably the carboxyl group of the subunit III C-terminal Val-81 provide some of seven essential oxygen ligands normally required for defining a Ca(2+)-binding site in proteins. It is probable, but not yet established that an oligomeric form of subunit III polypeptides is essential for forming the Ca(2+)-binding site. Based on the accepted models for the hairpin conformation of the subunit III, it does seem clear that the Ca(2+)-binding site can form on the lumenal side of the membrane in the functional CFo structure.
 ...
PMID:Subunit III of the chloroplast ATP-synthase can form a Ca(2+)-binding site on the lumenal side of the thylakoid membrane. 826 26


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>