Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cetyltrimethylammonium and n-octadecyldimethylsulfonium bromides inhibit the Clostridium perfringens phospholipase C-catalyzed hydrolysis of 1-S-phosphocholine-2-O-hexadecanoyl-1-mercapto-2-ethanol (1) at pH 7.5, 37 degrees C, mu = 0.15 with KCl. Mixed micelles containing 1 and either inhibitor are substrates for the enzyme and the fraction of activity remaining is a monotonic, but non-linear function of the mole fraction of inhibitor. Simple saturation kinetics are observed as the concentration of 1 is increased in mixed micelles containing a constant mole fraction of inhibitor. Inhibition constants for cetyltrimethylammonium and n-octadecyldimethylsulfonium bromides are 0.66 +/- 0.04 and 0.25 +/- 0.02 mM, respectively. The data suggest that the significant inhibition previously observed for soluble alkyldisulfonium salts (K50 for dodecamethylene-bis(dimethylsulfonium) bromide, 27 microM) is dependent upon bifunctional cationic interactions rather than hydrophobic binding.
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PMID:Inhibition of the Clostridium perfringens phospholipase C hydrolysis of a thiophosphate analog of lysophosphatidylcholine by micelle-bound ammonium and sulfonium cations. 180 98

Cyclodextrins form inclusion complexes with a wide range of guest molecules which wholly, or in part, fit into their hydrophobic cavity. Since no covalent bonds are formed in this complexation, the guests can subsequently be eluted. The possibility of such complexation was envisioned as a means of removing chlorinated furanones from drinking water. Using a combination of infrared and ultraviolet techniques, evidence is presented for inclusion complex formation between mucochloric acid and beta-cyclodextrin in acidic aqueous solutions. Ultraviolet evidence supports the conclusion that under these acidic conditions, mucochloric acid exists in its cyclic form. Solid samples of the mucochloric acid-beta-cyclodextrin complex could be isolated by recrystalization of a 1:1 mole ratio of the above compounds from water at pH approximately 2. Solid sample infrared (potassium bromide or Nujol) showed a carbonyl shift of approximately 20 cm-1 when mucochloric acid was compared to the mucochloric acid-beta-cyclodextrin complex. No such shift was found upon simply grinding together the above components. Thus the carbonyl shift is ascribed to inclusion complexation of mucochloric acid into the beta-cyclodextrin cavity. Melting point and thin-layer chromatographic analyses also yielded supporting evidence for the formation of solid mucochloric acid-beta-cyclodextrin complexes. Pilot studies with 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), suggest a similar beta-cyclodextrin-complex formation in acidic solutions.
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PMID:Effect of beta-cyclodextrin on mucochloric acid and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone. 185 9

The response to membrane surface charge of the glycerol headgroup of dimyristoyl-phosphatidylglycerol (DMPG) was investigated via deuterium and phosphorus-31 nuclear magnetic resonance spectroscopy. The membrane surface charge was manipulated by adding various amounts of neutral dimyristoylphosphatidylcholine (DMPC) and/or positively charged didodecyldimethylammonium bromide (DDAB) to the negatively charged DMPG, selectively deuterated at the alpha and beta segments of its glycerol headgroup. The deuterium and phosphorus-31 nuclear magnetic resonance spectra were all characteristic of random dispersions of liquid-crystalline lipids in a bilayer configuration. Differential scanning calorimetry showed that all mixtures investigated exhibited gel to liquid-crystalline phase transitions below 35 degrees C. Measurements of the deuterium quadrupole splitting and of the phosphorus-31 chemical shift anisotropy lead to the following observations. (1) Dilution of the negative surface charge density by the addition of DMPC had little effect on the quadrupole splitting from either alpha- or beta-deuterated DMPG. (2) Direct cancellation of the negative surface charge density by addition of DDAB led to a progressive decrease in the quadrupole splitting measured from alpha-deuterated DMPG, while the quadrupole splitting measured from beta-deuterated DMPG increased. For alpha-deuterated DMPG addition of 0.3 mole fraction of DDAB resulted in the appearance of two distinct quadrupole splittings. No such effect was observed for beta-deuterated DMPG.
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PMID:Response of the headgroup of phosphatidylglycerol to membrane surface charge as studied by deuterium and phosphorus-31 nuclear magnetic resonance. 193 79

A latent form of 'Ferrooxidase' exhibiting ferrocyanide-dependent O2 uptake was detected in the isolated spinach chloroplasts. Presence of a cationic detergent hexadecyl trimethyl ammonium bromide (CTAB) in the medium was essential to induce this activity. The association of this enzyme activity with photosystem II (PSII) particles as well as the ability of PSII particles to show oxidation of H2O2 (catalase like activity) indicated its possible relationship with water oxidation system. The protein catalysing this activity was purified to homogeneity and its molecular mass was found to be 34 kDa. The purified protein showed a complete dependence on an electron acceptor, namely ferricyanide, for the oxidation of H2O2. While with ferrocyanide in the presence of CTAB, the protein exhibits the ferrooxidase activity. For both activities, a sharp pH optima at 6.1 was observed. The km for H2O2 was 12.2 mM. The purified enzyme protein contained 4 atoms of calcium and 2 atoms of iron per mole of the enzyme. Unlike catalase, the enzyme reaction was insensitive to sodium azide even at 500 microM concentration. The enzyme was found to be sensitive to metal chelators like ethylene-glycol-bis-(beta-aminoethylether) N, N+ tetra acetic acid (EGTA) (2mM), alpha,alpha-dipyridyl (500 microM) and 1,10-orthophenanthroline (200 microM). The sensitivity of the reaction to alpha,alpha-dipyridyl and 1,10-orthophenanthroline suggested the involvement of Fe2+ in the reaction. Inhibition of enzyme activity by EGTA and restoration of activity by supplementation of CaCl2 to the EGTA-dialysed sample confirmed the absolute requirement for calcium for this activity. Calcium was absent in the EGTA-dialysed enzyme. Apart from these inhibitors, NaF and NH2OH were potent inhibitors of the enzyme reaction.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Isolation of 34 kDa protein from spinach chloroplasts having ferrooxidase and H2O2-dependent dark O2 evolution activities. 205 97

Chemical modification of tryptophan residues in antithrombin III by dimethyl (2-hydroxy-5-nitrobenzyl) sulfonium bromide (HNBSB) generates products with similar levels of modification (equivalent to 0.9 mole 2-hydroxy-5-nitrobenzyl [HNB] incorporated/mole of antithrombin III) but with high or low affinity for heparin-Sepharose. Upon digestion with pancreatic or neutrophil elastase the low affinity forms generate a product of molecular weight form (55 kDa) not seen in digests of native antithrombin III or modified forms with high affinity for heparin. When measured as loss of activity the observed rate of digestion of the latter in the absence of heparin was more rapid than that of native antithrombin III. The differences in digestion are considered to be related to conformation at differences between the various forms.
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PMID:Influence of tryptophan modification upon digestion of antithrombin III by elastase. 205 15

The possibility of regulating the retention and selectivity of monoalkyl- and polymethyl-substituted aromatic hydrocarbons in normal-phase high-performance liquid chromatography was investigated by modifying the non-polar (hexane) mobile phase with halide derivatives of hydrocarbons. Dichloromethane, chloroform, carbon tetrachloride and ethyl bromide were employed as modifiers. The decrease in relative retention for small mole fractions of modifier in the eluent increased with decrease in the polarity. The retention mechanism of the aromatic hydrocarbons is discussed. Chromatograms for the group separation of diesel fuel aromatic hydrocarbons are presented.
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PMID:Peculiarities of aromatic hydrocarbon retention in normal-phase high-performance liquid chromatography with eluents containing halide derivatives. 208 83

According to the reaction conditions selected, chemical modification of tryptophan residues in antithrombin III by dimethyl (2-hydroxy-5 nitrobenzyl) sulfonium bromide (HNBSB) generated products with similar levels of modification (equivalent to 0.9 mole 2-hydroxy-5-nitrobenzyl (HNB) incorporated/mole of antithrombin III) but with high or low affinity for heparin. These products were subjected to digestion by cyanogen bromide and shown to be modified equivalently in fragment II containing Trp 189 and Trp 225 and fragment III containing Trp 49. The molar level of incorporation of HNB into these fragments was similar in the high and low affinity forms. Both high and low affinity forms showed loss of heparin cofactor activity. A recovery of heparin cofactor activity towards coagulation factor Xa was observed upon prolonged storage of low affinity forms at -70 degrees C. It is considered that the loss of high affinity for heparin upon modification of antithrombin III arises from change or stabilization of conformation associated with tryptophan modification and is not a singular property of modification of Trp 49.
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PMID:Influence of chemical modification of tryptophan residues on the properties of human antithrombin III. 231 91

The phosphorylation of the internal and integral membrane (M1) protein of influenza virus was studied. Four points can be made based on the data: (1) The M1 contains at least two moles of phosphate per mole of M1. (2) Phosphorylation of M1 is conserved between influenza A, B and C viruses. Other characteristics of the M1 are also conserved, such as solubility in organic solvent, heterogeneity and ability to partition into lipid vesicles. (3) M1 is phosphorylated in cells infected with a vaccinia recombinant (vP273) containing only the gene of M1, either as a result of a vaccinia virus associated kinase or a cellular one. (4) The phosphate is located within or in close proximity to the major stretch of neutral and hydrophobic amino acids found in M1, as determined by analyzing cyanogen bromide fragments.
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PMID:The phosphorylation of the integral membrane (M1) protein of influenza virus. 234 33

Human bronchial mucin from a patient suffering from chronic bronchitis was solubilized in aqueous solution containing sodium azide and protease inhibitors and purified by Sepharose 4B and 2B column chromatography. The mucin was further purified by cesium bromide density gradient centrifugation. Sodium dodecyl sulfate-polyacrylamide gel (7.5%) electrophoresis of this material showed high-molecular-weight mucin component(s) at the top of the gel. Chemical analysis of this preparation indicated a typical mucin profile of amino acids and carbohydrates. Ion-exchange chromatography resulted in resolution of the purified mucin into neutral and acidic fractions. Comparison of the chemical composition of these two fractions showed higher mole percentage of threonine, serine, sialic acid, and sulfate in the acidic fraction. Chemical deglycosylation of the purified mucin preparation with trifluoromethane sulfonic acid was carried out at 20 degrees C for 3 1/2 h. Sialic acid, fucose, galactose, and N-acetylglucosamine were completely removed, whereas traces of N-acetylgalactosamine were still detected. High-pressure liquid chromatography of the deglycosylated products from native, neutral, and acidic mucin preparations resulted in a principal peptide, P1, with identical amino acid composition. Cyanogen bromide (CNBr) treatment of the peptide P1 from neutral and acidic mucins and subsequent fractionation of the fragments by high-pressure liquid chromatography resulted in similar peptide profiles. The P1 peptide fraction was further subjected to high-pressure liquid chromatography in a second solvent system, which resulted in two peaks, P1a and P1b. Gel filtration of both peptides in 6 M guanidine hydrochloride indicated a single peak with molecular weight of approximately 97 kDa. The amino acid profile of the two peptides was dominated by high levels of threonine, serine, and proline, which combined accounted for nearly 39% of the total residues, and in most respects, the profile resembled that of native mucin. End-group analysis of the peptide P1a indicated a blocked N-terminus, whereas serine was found to be the N-terminal amino acid in the peptide P1b. Rabbit antibodies prepared against the peptide P1 from native tracheal mucin reacted strongly with neutral and acidic mucin as well as the mucin from human colon. Both neutral and acidic human tracheal mucins were immunologically reactive with mouse monoclonal antibody HMPFG-2, which was prepared against human mammary mucin. However, the response of this antibody to human colonic mucin was rather weak.
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PMID:Neutral and acidic human tracheobronchial mucin. Isolation and characterization of core protein. 237 52

1. Multiple conductance level ion channels were recorded in excised and cell-attached patches from cells of a mouse B lymphocyte hybridoma line. The reversal potential for the single-channel current was unaffected by the species of cation on the cytoplasmic face of the patch, but changed as the Cl- concentration was altered, indicating that the channel is anion selective. 2. The permeability sequence determined from reversal potentials was F- greater than I- greater than SCN- greater than Br- greater than Cl- greater than glucuronate greater than NO3- greater than aspartate. This was different from the conductance sequence (Cl- greater than SCN- = F- greater than Br- greater than NO3- greater than I- greater than glucuronate greater than aspartate), indicating interaction of ions within the pore of the channel. Consistent with this was the observation of anomalous mole fraction dependence with a mixed solution of thiocyanate and chloride. 3. In addition to the main open level (about 400 pS; excised patch, symmetrical 165 mM-Cl-), three subconductance levels and one supraconductance level were observed. These were concluded to be integral components of the same channel based on coincidence of appearance and identical permeabilities. 4. The channel is voltage dependent, with open probability in excised patches increasing with more positive potentials. The channel was reversibly blocked in a voltage-dependent manner by SITS (4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid), a stilbene derivative, on the cytoplasmic face. 5. Several differences were noted between cell-attached and excised-patch recordings. The multiple conductance level channel was less frequently seen in cell-attached patches but could often be induced to appear by prolonged application of positive voltages. This induced channel in attached patches showed an altered voltage dependence which could be partially mimicked in excised patches by including cyclic AMP and ATP in the solution on the cytoplasmic side of the membrane.
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PMID:Anion channels with multiple conductance levels in a mouse B lymphocyte cell line. 247 28


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