ChlD mutants of Escherichia coli are pleiotropic, lacking formate-nitrate reductase activity as well as formate-hydrogenlyase activity. Whole-chain formate-nitrate reductase activity, assayed with formate as the electron donor and measuring the amount of nitrite produced, was restored to wild-type levels in the mutants by addition of 10-4 M molybdate to the growth medium. Under these conditions...

In the form of molybdate the transition metal molybdenum is essential for plants as it is required by a number of enzymes that catalyze key reactions in nitrogen assimilation, purine degradation, phytohormone synthesis, and sulfite detoxification. However, molybdate itself is biologically inactive and needs to be complexed by a specific organic pterin in order to serve as a permanently bound pr...

ModA, the periplasmic-binding protein of the Escherichia coli mod transport system was overexpressed and purified. Binding of molybdate and tungstate to ModA was found to modify the UV absorption and fluorescence emission spectra of the protein. Titration of these changes showed that ModA binds molybdate and tungstate in a 1:1 molar ratio. ModA showed an intrinsic fluorescence emission spectrum...

chlD mutants of Escherichia coli lack active nitrate reductase but form normal levels of this enzyme when the medium is supplemented with 10-3 M molybdate. When chlD mutants were grown in unsupplemented medium and then incubated with molybdate in the presence of chloramphenicol, they formed about 5% the normal level of nitrate reductase. Some chlD mutants or the wild type grown in medium supple...

A theoretical analysis was carried out of the mechanism and kinetics of methane oxidation to formaldehyde occurring on isolated molybdate species supported on silica. Both mono-oxo and di-oxo molybdate structures were used to represent the active centers. The energetics for each elementary reaction was determined from density functional theory calculations, and the entropy changes were determin...

In the presence of 10 mM molybdate ion, we are able to detect the appearance of a [6,7-3H]-17,21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione-([3H]R5020) binding moiety in human prostatic cytosol which sedimented at approximately 8S in a glycerol density gradient. The specifically bound [3H]-R5020 was displaced by progesterone, tiramcinolone acetonide, and R5020 but not by cortisol, dihydrotestos...

The effect of adenylate cyclase activation on the in vitro contractures of control and malignant hyperpyrexia susceptible (MHS) porcine muscle was investigated. While fluoride and molybdate ions potentiated drug-induced contractures in control muscle, other activators of adenylate cyclase (forskolin and noradrenaline) did not. Furthermore, fluoride and molybdate had no effect on MHS skeletal mu...

The title compound, bis-[4,4'-(propane-1,3-di-yl)-dipiperidin-ium] β-octa-molybdate(VI), (C(13)H(28)N(2))(2)[Mo(8)O(26)], was produced by hydro-thermal reaction of an acidified aqueous solution of Na(2)MoO(4)·2H(2)O and 4,4'-trimethyl-ene-dipiperidine (L). The structure of the title compound consists of β-octa-molybdate(VI) anion clusters and protonated [H(2)L](2+) cations. The octa-molybdate a...

The title compound, bis-[2,2'-dimethyl-3,3'-(butane-1,4-di-yl)diimidazol-1-ium] β-octa-molybdate(VI), (C(12)H(20)N(4))(2)[Mo(8)O(26)], was produced by hydro-thermal reaction of an acidified aqueous solution of Na(2)MoO(4) and 1,4-bis-(2-methyl-1H-imidazol-1-yl)butane (hereafter L). The structure of the title compound consists of the β-octa-molybdate anions having a center of symmetry, and proto...

This work reports the preparation of a Tc generator based on conversion of Mo produced by neutron irradiation, into insoluble magnesium Mo-molybdates compounds as matrix. The effect of magnesium salt types and concentration, Mg:Mo molar ratios, pH of molybdate solutions, eluate volume as well as the addition order of molybdate and magnesium solutions’ influences on the final Tc were evaluated. ...