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)

Oxidation of p-nitro- and p-dimethylaminomethyl derivatives of benzylamine, catalyzed by amine oxidases from human placenta and blood serum, was studied. The amine oxidase activity was estimated by means of a spectrophotometric procedure involving measurement of aldehyde formed during the reaction after extraction with hexane. For extraction of benzaldehyde and p-nitrobenzaldehyde in the samples HCl was added up to the concentration of 0.17 M and for extraction of p-dimethylaminomethyl benzaldehyde--NaHCO3 up to the 0.5 M concentration. The reaction products were extracted with a yield of 94%, 83% and 78% respectively; molar extinction coefficients for aldehydes at the maximal absorption were equal to 13,080 (241 mn), 16,520 (258 nm), and 11,547 (248 nm), respectively. Analysis of the oxidative reactions using inhibitors Lilly 51,641, deprenyl, aminoguanidine and semicarbazide showed that monoamine oxidase of the A type (95%) and benzylamine oxidase (7%) catalyzed oxidation of 0.1 mM p-nitrobenzylamine in mitochondria and microsomes but oxidation of the substrate at 1 mM concentration was catalyzed by monoamine oxidase of the B type (20% in mitochondria and 35% in microsomes). In the soluble fraction oxidation of p-nitrobenzylamine was catalyzed mainly by diamine oxidase (55%); monoamine oxidase of the A type catalyzed oxidation of 30% of the amine, benzylamine oxidase-15%. The molecular activity of the mitochondrial monoamine oxidase of the A type with p-nitrobenzylamine as a substrate was equal to 61 nmol of the product per 1 mole of the enzyme per 1 min.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Oxidation of p-nitrobenzylamine and p-dimethylaminomethylbenzylamine by amine oxidases from the human placenta and serum]. 370 5

The initial velocity of coagulation of human oxyhemoglobin in tris-HCl buffer measured by turbidimetric method, pH 7.2 in the presence of phenylmercuryacetate made it possible to estimate the amount of moles of this reagent stechiometrically binding with hemoglobin without coagulation of the latter. At 15-30 degrees C this amount is 30-34 mole per hemoglobin-tetramer. At temperature increase from 30 to 42.5 degrees C the amount of the reagent necessary for protein coagulation sharply decreases. A model is proposed assuming that oxyhemoglobin coagulation proceeds only during binding of the reagent with specific protein sites.
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PMID:[Study of hemoglobin structure by a turbidimetric method]. 380 22

The protonation equilibrium and hydrophobic character of lidocaine were characterized by its pKa and the octanol:buffer partition coefficients of the charged (P+) and neutral (Po) drug species. These measurements were accomplished by ultraviolet spectrophotometry of pure lidocaine HCl solutions at different temperatures, ionic strengths, and buffer concentrations. Corroboration of the pKa determination by the potentiometric method and of the partition coefficients by gas chromatography validated the general application of the spectrophotometric technique. The pKa increased with decreasing temperature (7.61 +/- 0.06 at 36 degrees C; 7.94 +/- 0.04 at 26 degrees C, in water; mean +/- SD), increasing ionic strength (8.06 +/- 0.02 at 26 degrees C in 0.165 M NaCl) and increasing buffer capacity (8.28 +/- 0.06 at 25 degrees C in 0.15 M NaCl + 20 mM buffer). Octanol:buffer partition coefficients for both the protonated and the neutral species (expressed as mole fractions) increased upon warning: 0.55 +/- 0.04 and 2666 +/- 202, respectively, at 25 degrees C, and 0.75 +/- 0.09 and 3210 +/- 272, respectively, at 36 degrees C. Ionic strength and buffer concentration had no significant effect on either P value. The increase in pKa at lower temperatures coupled with the decreased partition coefficients resulted in a nearly constant concentration of the protonated species in octanol as the system was cooled, whereas the concentration of the neutral species fell by more than 80%. This finding may explain the large increase in the impulse blocking potency of lidocaine observed upon nerve cooling, if the protonated anesthetic species is the more active form of the drug competing with the neutral species for a common binding site.
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PMID:Fundamental properties of local anesthetics. I. The dependence of lidocaine's ionization and octanol:buffer partitioning on solvent and temperature. 381 59

The conventional activity of electrophoretically purified horseradish peroxidase toward guaiacol, pyrogallol, 2,6-dimethoxyphenol, and benzidine is abolished by removal of the heme prosthetic group with a mixture of cold acetone and hydrogen chloride. The apoenzyme, though devoid of peroxidase activity, retains its activity as an indoleacetic acid oxidase when it is supplied with 10(-5) mole of manganous ion and 2,4-dachlorophenol per liter. This oxidase activity is cyanide-sensitive; azide also inhibits under specific conditions of both pH and cofactor concentration. Partial restoration of the peroxidase activity by recombination of apoprotein with heme produces no effect on the oxidase activity, except that cofactors are no longer absolutely required. Therefore, it appears that the activity of peroxidase as an indoleacetic acid oxidase need not directly involve the heme prosthetic group, or that manganous ions and dichlorophenol can substitute for the heme group in the reaction between indoleacetic acid and oxidase.
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PMID:Indoleacetic acid oxidase activity of apoperoxidase. 603 67

The activation of ovine brain glutamine synthetase by Mn(II) or Mg(II) was studied by steady-state kinetics. The metal ion concentration was varied at several fixed concentrations of ATP, and vice versa, and the resultant kinetic curves were analyzed according to the method of London and Steck [London, W. P., & Steck, T. L. (1969) Biochemistry 8, 1767-1779]. The data for Mg(II) indicated optimal activation at Mg:ATP = 2:1, whereas that for Mn(II) occurred at Mn:ATP = 1:1. This was interpreted as indicating formation of Mg . E . Mg . ATP as the subunit complex of optimum activity with Mg(II) (pHopt 7.5). With Mn(II) (pHopt 5.0), the complex of optimum activity may be either E . Mn . ATP or Mn . E . Mn . ATP, where the Mn . E complex is very tight. So that the latter two possibilities could be distinguished, titrations of the enzyme with Mn(II) were performed, electron paramagnetic resonance being used to determine free Mn(II). Four moles of Mn(II) ions was found to bind per mole of octameric enzyme, with an apparent Kd congruent to 0.54 microM. Addition of either HCl or Nd(III) ions to Chelex-treated enzyme results in the release of 3.7 +/- 0.2 Mn(II) ions. Thus, it appears that four Mn(II) are very tightly bound per octamer and that four more Mn(II) can bind tightly. Neither Mg(II) nor Ca(II) at 50 mM can displace Mn(II) from the Mn4 . E complex, but Mn(II) still binds tightly to apoenzyme or Mn4E in the presence of 50 mM Mg(II). As one proceeds from apo-E to Mn4 . E to Mn4 . E . Mn4 (+/- ATP), the intensity of the fluorescence emission of protein tryptophan residues decreases strongly and successively. The specific activities of the apo-E, Mn4 . E, and Mn4 . E . Mn4 complexes were found to be 0, 50, and 200 units/mg, respectively. If apoenzyme is added to a continuous coupled assay system with Mg(II), buffer, and with or without Mn(II) present, a time-dependent activation is observable with t1/2 congruent to 0.5-1.0 min. The total intracellular concentration of Mn(II) in ovine brain tissue was determined to be 1.9-2.6 microM, whereas the free [Mn(II)] was below 0.5 microM. Since the enzyme binds Mn(II) in preference to other divalent ions, it appears that the enzyme may exist as a manganoenzyme in vivo.
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PMID:Glutamine synthetase from ovine brain is a manganese(II) enzyme. 612 92

The base-release activity of oxygen adduct of bleomycin-Fe(II) complex [BLM-Fe(II)] from DNA decreased with a half-life of 5.2 minutes, when incubated at 0 degrees C in 0.05 M Tris-HCl buffer at pH 7.8 in the absence of DNA. Under the same condition, however, visible and ESR spectra showed that the adduct was immediately converted into the ferric complex. The ESR study further indicated the simultaneous formation of two kinds of the low-spin BLM-Fe(III) complex. One of them disappeared in parallel with the decrease of the base-release activity and transformed into the other. The latter Fe(III) complex was stable but inactive. However, by addition of hydrogen peroxide to the latter, the former was regenerated and the base-release activity appeared. Oxygen concentration measurements by oxygraph showed that one mole of BLM-Fe(II) consumed approximately 0.5 mole of molecular oxygen instantly, but did not any more thereafter in the absence of a reducing agent. While in the presence of 2-mercaptoethanol, the oxygen consumption proceeded biphasically, and equimolar oxygen was consumed by BLM-Fe(II) in the first rapid reaction. These results suggest that oxygen adduct of BLM-Fe(II) is reduced by one electron transfer from an external electron donor and the resulting BLM-Fe(III)-O2H- [or its deprotonated form: BLM-Fe(III)-O2(2)-] shows the activity to break DNA accompanying the base-release.
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PMID:An active intermediate formed in the reaction of bleomycin-Fe(II) complex with oxygen. 616 29

An insoluble complex was synthesized by the reaction of sodium diethyldithiocarbamate trihydrate (DDTC) with CdCl2 X 2.5 H2O (Cd). Elemental analyses of the product yielded a percent composition of each element which was consistent with the postulated structure of two mole equivalents of (DDTC)- and one mole equivalent of Cd++. The DDTC formed a complex with 11 other metal ions tested, but not with Ca++ or Mg++. The complex with Cd was highly insoluble in water, 0.1 N HCl, 0.1 N NaOH, human serum, and carbon tetrachloride, but it was soluble in pure dimethyl sulfoxide. The DDTC protected mice from a greater than LD100 dose of Cd. This protective effect was more pronounced when DDTC treatment was delayed at least 30 min after i.p. administration of Cd. More than 98 percent of mice treated with 500 mg per kg of DDTC 30 min to five hrs after Cd administration survived, and 50 percent survived when treatment wad delayed for eight hrs. Administration of DDTC prior to or immediately after Cd gave less protection. The lowest (DDTC)-/Cd++ molar dose ratio which resulted in 100 percent survival following the otherwise lethal dose of Cd was 7.6, which was less than four times the theoretical stoichiometric molar ratio for formation of the complex. The LD50 of the complex in mice wa approximately 650 mg per kg of the i.p. route, indicative of a low degree of dissociation in vivo.
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PMID:Diethyldithiocarbamate in treatment of acute cadmium poisoning. 627 69

Treatment of yeast fatty acid synthetase with pyridoxal 5'-phosphate inhibited the enzyme. Assays of the partial activities of the pyridoxal phosphate-treated synthetase showed that only the beta-ketoacyl reductase was significantly inhibited. NADPH prevented inactivation of the enzyme by pyridoxal phosphate, indicating that pyridoxal modifies a residue near or in the beta-ketoacyl reductase site. The pyridoxal-treated synthetase shows a fluorescence spectrum with a maximum of 426 nm after uv irradiation at 325 nm. Binding of the pyridoxal phosphate to the synthetase is reversible as shown by the disappearance of the fluorescence band after dialysis of pyridoxal-treated enzyme. Reduction with NaBH4 of the pyridoxal-treated enzyme eliminates this fluorescence maximum and causes the appearance of a new band at 393 nm. These observations suggest that pyridoxal phosphate interacts with the synthetase by forming a Schiff base with lysine residue at the beta-ketoacyl reductase site. Amino acid analyses of the HCl hydrolysates of the borohydride-reduced, pyridoxal-treated synthetase showed the presence of 6 mol of N6-pyridoxal derivative of lysine per mole of fatty acid synthetase, indicating the presence of six sites of beta-ketoacyl reductase in the native enzyme. Autoradiography of sodium dodecyl sulfate-polyacrylamide gels of the pyridoxal phosphate enzyme reduced with NaB3H4 indicates that the alpha subunit contains the beta-ketoacyl reductase domain. These findings are consistent with the proposed structure of the alpha 6 beta 6 complex required for palmitoyl-CoA synthesis.
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PMID:Inactivation of yeast fatty acid synthetase by modifying the beta-ketoacyl reductase active lysine residue with pyridoxal 5'-phosphate. 641 72

A combination of equilibrium dialysis and ultrafiltration has been used to demonstrate the conservation of charge in the interaction between bovine serum albumin and methyl orange in Tris-HCl buffer, pH 7.4, I = 0.05 M; and also in the dimerization of alpha-chymotrypsin in acetate/chloride buffer, pH 3.9, I = 0.11 M, containing various concentrations of indole (0-10 mM) in order to displace the equilibrium position towards monomer. In the former study the magnitude of the negative charge on the albumin was shown to increase linearly with the number of molecules of methyl orange bound to the protein, the observed slope (0.96 +/- 0.08) of this relationship being in excellent agreement with that predicted on the basis of charge conservation for attachment of the univalent, negatively charged methyl orange ligand. In the study of alpha-chymotrypsin, the net charge (expressed per monomeric enzyme unit) was +10 in solutions in which the mole fraction of monomer varied between 0.47 and 0.88, the extent of this range having been established by means of constituent association equilibrium constants obtained from sedimentation equilibrium studies.
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PMID:Experimental tests of charge conservation in macromolecular interactions. 668 38

Hemolysates were treated with HCl (0.18 M)-acetone solution to remove heme and the globin precipitated was washed with acetone. It was dissolved in 1 ml of 0.05 M Tris-HCl, pH 7.0, subjected to heat treatment for 10 min at 100 degrees C to remove traces of acetone, and treated with 0.05 ml of 80% phenol and 3 ml of H2SO4. The color was measured at 480 nm. Glucosylhemoglobin values in control subjects and diabetics were respectively 0.286 +/- 0.051 and 0.513 +/- 0.081 mole hexose/mole hemoglobin. The increase in diabetics was highly significant (P less than 0.001). A good correlation (r = 0.85) between fasting blood sugar values and glucosylhemoglobin level was observed. When globin solution was subjected to 4 hr hydrolysis with HCl-oxalic acid (2 and 1 mole/liter) solution prior to phenol-sulfuric acid reaction, estimated glucosylhemoglobin values increased to 0.720 +/- 0.083 in control subjects and 1.036 +/- 0.115 in diabetics. The possible reasons for this increase are discussed.
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PMID:A short-duration colorimetric method based on phenol-sulfuric acid reaction for the estimation of glucosylhemoglobin. 674 99


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