A vanadate-stimulated NADH oxidase in erythrocyte membrane generates hydrogen peroxide

Oxidation of NADH by rat erythrocyte plasma membrane was stimulated by about 50-fold on addition of decavanadate, but not other forms of vanadate like orthovanadate, metavanadate aad vanadyl sulphate. The vanadate-stimulated activity was observed only in phosphate buffer while other buffers like Tris, acetate, borate and Hepes were ineffective. Oxygen was consumed during the oxidation of NADH and the products were found to be NAD+ and hydrogen peroxide. The reaction had a stoichiometry of one mole of oxygen consumption and one mole of H2O2 production for every mole of NADH that was oxidized. Superoxide dismutase and manganous inhibited the activity indicating the involvement of superoxide anions. Electron spin resonance in the presence of a spin trap, 5, 5prime-dimethyl pyrroline N-oxide, indicated the presence of superoxide radicals. Electron spin resonance studies also showed the appearance of VIV species by reduction of VV of decavanadate indicating thereby participation of vanadate in the redox reaction. Under the conditions of the assay, vanadate did not stimulate lipid peroxidation in erythrocyte membranes. Extracts from lipid-free preparations of the erythrocyte membrane showed full activity. This ruled out the possibility of oxygen uptake through lipid peroxidation. The vanadate-stimulated NADH oxidation activity could be partially solubilized by treating erythrocyte membranes either with Triton X-100 or sodium cholate. Partially purified enzyme obtained by extraction with cholate and fractionation by ammonium sulphate and DEAE-Sephadex was found to be unstable.

Metabolism of geraniol and linalool in the rat and effects on liver and lung microsomal enzymes

1. Metabolites isolated from the urine of rats after oral administration of geraniol (I) were: geranic acid (II), 3-hydroxy-citronellic acid (III), 8-hydroxy-geraniol (IV), 8-carboxy-geraniol (V) and Hildebrandt acid (VI). 2. Metabolites isolated from urine of rats after oral administration of linalool (VII) were 8-hydroxy-linalool (VIII) and 8-carboxy-linalool (IX). 3. After three days of feeding rats with either geraniol or linalool, liver-microsomal cytochrome P-450 was increased. Both NADH- and NADPH-cytochrome c reductase activities were not significantly changed during the six days of treatment. 4. Oral administration of these two terpenoids did not affect any of the lung-microsomal parameters measured.

Non-Abelian monopoles break color. I. Classical mechanics

Monopoles which are sources of non-Abelian magnetic flux are predicted by many models of grand unification. It has been argued elsewhere that a generic transformation of the "unbroken" symmetry group H cannot be globally implemented on such monopoles for reasons of topology. In this paper, we show that similar topological obstructions are encountered in the mechanics of a test particle in the field of these monopoles and that the transformations of H cannot all be globally implemented as canonical transformations. For the SU(5) model, if H is SU(3)C×U(1)em, a consequence is that color multiplets are not globally defined, while if H is SU(3)C×SU(2)WS×U(1)Y, the same is the case for both color and electroweak multiplets. There are, however, several subgroups KT, KT′,… of H which can be globally implemented, with the transformation laws of the observables differing from group to group in a novel way. For H=SU(3)C×U(1)em, a choice for KT is SU(2)C×U(1)em, while for H=SU(3)C×SU(2)WS×U(1)Y, a choice is SU(2)C×U(1)×U(1)×U(1). The paper also develops the differential geometry of monopoles in a form convenient for computations.

Photolysis of the dithiolactone 4-isopropylidene-3,3-dimethyl-1-thietan-2-thione; a Norrish type I reaction

The dithiolactone (1) upon excitation gives the dithione (2) in cyclohexane and other aprotic solvents and a 1 : 1 adduct in hydroxylic solvents from an n* excited singlet state via an -cleavage process.

Immunologic studies on nucleic acids and their components. I. An analysis of the specificity of anti-deoxyadenylate antibodies by a membrane-binding technique

Anti-deoxyadenylate antibodies were produced in rabbits by injecting a conjugate of deoxyadenosine 5′-phosphate with bovine serum albumin. The antisera, as analyzed by double diffusion in agar and the quantitative precipitin reaction, showed hapten-specific antibodies. The specific interaction between [3H]deoxyadenylate and antiserum was studied by a sensitive nitrocellulose membrane-binding assay. The specificity of the antibodies was analyzed by measuring the effectiveness of other nucleotides or derivatives to inhibit the hapten-antibody binding. The requirements for recognition by the antibody sites were studied by using a series of naturally occurring nucleic acid components as well as some synthetic derivatives as inhibitors. The antibodies were found to show a high degree of specificity for the whole nucleotide, the base, sugar and phosphate playing almost equally important roles. There was cross reactivity with other mononucleotides, although of a low order. The antibodies were able to react with DNA and tRNA.

Studies on the synthesis of cytochrome P-450 and cytochrome P-448 in rat liver

The synthesis of cytochrome P-450 (phenobarbital inducible) and cytochrome P-448 (3-methylcholanthrene inducible) have been studied in rat liver in vivo and in the wheat germ cell-free system using anti- cytochrome P-450 and anti-cytochrome P-448 antibodies. The major mature forms synthesized in vivo correspond to a molecular weight of 47,000 for cytochrome P-450 and 53,000 for cytochrome P-448. Translation of poly(A)-containing RNA from phenobarbital-treated rats in the wheat germ cell-free system reveals that the cell-free product immunoprecipitated with anti-cytochrome P-450 antibody has a molecular weight close to 47,000. In the case of 3-methylcholanthrene, the cell- free product immunoprecipitated with anti-cytochrome P-448 antibody shows a molecular weight around 59,000. Significant conversion of the 59,000 species to the 53,000 species can be demonstrated when the translation is carried out in the presence of microsomal membranes isolated from rat liver. Phenobarbital and 3-methylcholanthrene enhance the translatable messenger.

Mechanism of adsorption effects on electrode kinetics: Part I: Selection rules in the case of low coverage by molecular surfactants

It is shown that the effect of adsorption of inert molecules on electrode reaction rates is completely accounted for, by introducing into the rate equation, adsorption-induced changes in both the effective electrode area as well as in the electrostatic potential at the reaction site with an additional term for the noncoulombic interaction between the reactant and the adsorbate. The electrostatic potential at the reaction site due to the adsorbed layer is calculated using a model of discretely-distributed molecules in parallel orientation when adsorbed on the electrode with an allowance for thermal agitation. The resulting expression, which is valid for the limiting case of low coverages, is used to predict the types of molecular surfactants that are most likely to be useful for acceleration and inhibition of electrode reactions.

Einstein relation in n-i-p-i and microstructures of nonlinear optical, optoelectronic and related materials: Simplified theory, relative comparison and suggestions for an experimental determination

We investigate the Einstein relation for the diffusivity-mobility ratio (DMR) for n-i-p-i and the microstructures of nonlinear optical compounds on the basis of a newly formulated electron dispersion law. The corresponding results for III-V, ternary and quaternary materials form a special case of our generalized analysis. The respective DMRs for II-VI, IV-VI and stressed materials have been studied. It has been found that taking CdGeAs2, Cd3As2, InAs, InSb, Hg1−xCdxTe, In1−xGaxAsyP1−y lattices matched to InP, CdS, PbTe, PbSnTe and Pb1−xSnxSe and stressed InSb as examples that the DMR increases with increasing electron concentration in various manners with different numerical magnitudes which reflect the different signatures of the n-i-p-i systems and the corresponding microstructures. We have suggested an experimental method of determining the DMR in this case and the present simplified analysis is in agreement with the suggested relationship. In addition, our results find three applications in the field of quantum effect devices.

Mixed ligand complexes in vinyl polymerization. I. [N,N-ethylenebis (salicylideneiminato)](acetylacetonato)cobalt(III) as an initiator

Polymerization of methyl methacrylate in the presence of a mixed ligand complex, [N,N-ethylenebis(salicylideneiminato)](acetylacetonato)cobalt(III) in benzene was studied. The rate of polymerization was proportional to the square root of the concentration of the chelate and the monomer exponent was 1.67 and 1.69 at 60 and 70°C, respectively. The activation energy and the kinetic and transfer constants were evaluated. A free-radical mechanism has been proposed.

2-Thioacetamido thiazole as an ambidentate ligand. Complexes of Zn(II), Cd(II), Hg(II) and Cu(I)

Metal complexes of thiazoles have been studied in recent years[I-3] because of their biochemical importance[4,5]. However, data on metal complexes of thiazole derivatives containing another coordinating function are limited[2]. We have synthesized and examined the donor characteristics of a new ligand, 2-thioacetamide thiazole (TATZ)(I) towards chlorides and bromides of Zn(II), Cd(II), Hg(II) and Cu(I). The presence of four potential donor atoms and extensive charge delocalization should render TATZ a versatile ligand.

Gas-crystal photoreaction: the structures of 4,4'-dimethoxy(thiobenzophenone) (I), C15H14O2S, and 4,4'-bis(dimethylamino)thiobenzophenone (II), C17H20N2S

(I): M r = 258.34, triclinic, Pi, a = 9.810 (3), b=9.635(3), e=15.015(4)A, a=79.11(2), #= 102.38 (3), y = 107.76 (3) o, V= 1308.5 A 3, Z = 4, Din= 1.318 (3) (by flotation in KI solution), D x = 1.311 g cm -3, Cu Ka, 2 = 1.5418/~, g = 20-05 cm -1, F(000) = 544, T---- 293 K, R = 0.074 for 2663 reflections. (II): M r = 284.43, monoclinic, P2~/c, a= 17.029 (5), b=6.706 (5), c= 14.629 (4), t= 113.55 (2) ° , V=1531.4A 3, Z=4, Dm=1.230(5) (by flotation in KI solution), Dx= 1.234gem -3, Mo Ka, 2 = 0.7107 A, g = 1.63 cm-1; F(000) = 608, T= 293 K, R = 0.062 for 855 reflections. The orientation of the C=S chromophores in the crystal lattice and their reactivity in the crystalline state are discussed. The C--S bonds are much shorter than the normal bond length [1.605 (4) (I), 1.665 (8) A (II) cf. 1.71 A].

4-Biphenylyl phenyl thioketone (I), C19H14S, and 1-naphthyl phenyl thioketone (II), C17H12S

(I): Mr=274"39, orthorhombic, Pbca, a = 7.443 (1), b= 32.691 (3), c= 11.828 (2)A, V= 2877.98A 3, Z=8, Din= 1.216 (flotation in KI), D x = 1.266 g cm -3, /~(Cu Ka, 2 = 1.5418 A) = 17.55 cm -1, F(000) = li52.0, T= 293 K, R = 6.8%, 1378 significant reflections. (II): M r = 248.35, orthorhombic, P212~21, a = 5.873 (3), b = 13.677 (3), c = 15-668 (5) A, V = 1260.14 A 3, Z = 4, D,n = 1.297 (flotation in KI), Dx= 1.308 g cm -a, /t(CuKa, 2=1.5418 A) = 19.55 cm -~, F(000) = 520.0, T= 293 K, R = 6.9%, 751 significant reflections. Crystals of (I) and (II) undergo photo-oxidation in the crystallinestate. In (I) the dihedral angle between the phenyl rings of the biphenyl moiety is 46 (1) °. The C=S bond length is 1.611(5) A in (I) and 1.630 (9)/~ in (II). The correlation between molecular packing and reactivity is discussed.

Thermal stabilization of glucose oxidase and glucoamylase by physical entrapment

Physical entrapment was used as an approach to achieve thermal stabilization of enzymes. The ti values for the thermoinactivation of glucose oxidase and glucoamylase were increased several-fold by their entrapment in polyacrylamide gels. In polyacrylate gels the individual enzymes behaved differently, probably owing to microenvironmental effects arising by the polyelectrolyte nature of the carrier.