Peroxochromium(IV) complexes are putative DNA-damaging and mutagenic agents in chromium(VI)-mediated carcinogenesis. The reaction between aquaethylenediaminebis(peroxo)chromium(IV) and glutathione at neutral pH exhibits a cyclic redox process displaying a persistent recycling of Cr(IV) and Cr(VI) with the intervention of chromium(V) intermediates. The coordination by a glutathione molecule trig...

An accepted mechanism for mitochondrial oxidation of fatty acids, i.e. ,8 oxidation, although inferred to apply also to long chain fatty acids (>C&), has actually been elucidated only for relatively short chain acids (<C’S); only the activation (acyl coenzyme A synthetase) and initial dehydrogenation (acyl coenzyme A dehydrogenase) steps have been demonstrated for palmitate (1). The present pap...

The enzymes of mitochondrial beta-oxidation are thought to be organized in at least two functional complexes, a membrane-bound, long-chain-specific beta-oxidation system and a matrix system consisting of soluble enzymes with preferences for medium-chain and short-chain substrates. This hypothesis is supported by the observation that the inactivation of long-chain 3-ketoacyl-CoA thiolase by 4-br...

The ESR-spin stabilization approach has been employed to detect and characterize o-semiquinone radicals from the oxidation of epinephrine and related materials (norepinephrine, 3,4-dihydroxynorephedrine, isoproterenol, and adrenalone) in aqueous solutions. Semiquinones were generated by various oxidative procedures--enzymatic oxidation (with horseradish peroxidase/H2O2), chemical oxidation (wit...

1. Rat liver mitochondria oxidizing [16-14C]palmitoylcarnitine accumulate saturated long-chain thiester intermediates which may be detected by radio-g.1.c.2. Time-courses of intermediate accumulation display no product-precursor relationships and the end product, measured as [14C]citrate, is produced without a detectable initial lag. 3. A short pulse of [16-14C]palmitoylcarnitine followed by un...

In the search for new efficacious antibiotics, biosynthetic engineering offers attractive opportunities to introduce minor alterations to antibiotic structures that may overcome resistance. Dbv29, a flavin-containing oxidase, catalyzes the four-electron oxidation of a vancomycin-like glycopeptide to yield A40926. Structural and biochemical examination of Dbv29 now provides insights into residue...

Reduction potentials and pK(a) values were calculated for intermediates and products along three major pathways for guanine oxidation using the B3LYP and CBS-QB3 levels of theory with the SMD implicit solvation model. N-methylated nucleobases were used as models for nucleoside species. Ensemble averaged reduction potentials at pH 7 (E7) were obtained by combining calculated standard reduction p...

This work presents the first combined experimental and computational study that gives evidence of the electrophilic reactivity of a nonheme iron(III)-hydroperoxo species. We show that in contrast to their heme counterparts the nonheme iron(III)-hydroperoxo complexes are catalytically much more active and even more so than nonheme iron(IV)-oxo species.

Current catalysts for the alcohol oxidation in fuel cells (typically noble metals-based) are susceptible to poisoning with intermediates like CO. Hence we decided to find superseded catalysts for methanol oxidation based on incorporation of mixed oxides. In this research, a nano-size perovskite SrFeO3-δ (SrFeO3<su...

Trichloroethylene (TCE)-transforming aquifer methanotrophs were evaluated for the influence of TCE oxidation toxicity and the effect of reductant availability on TCE transformation rates during methane starvation. TCE oxidation at relatively low (6 mg liter-1) TCE concentrations significantly reduced subsequent methane utilization in mixed and pure cultures tested and reduced the number of viab...