The green fluorescent protein (GFP) of the jellyfish Aequorea victoria offers certain advantages over other bioluminescence systems because no exogenously added substrate or co-factors are necessary, and fluorescence can be elicited by irradiation with blue light without exposing the cells producing GFP to invasive treatments. A mycobacterial shuttle-plasmid vector carrying gfp cDNA was constru...

Bacteria are exposed to reactive oxygen species from the environment and from those generated by aerobic metabolism. Catalases are heme proteins that detoxify H(2)O(2), and many bacteria contain more than one catalase enzyme. Also, the nonheme peroxidase alkyl hydroperoxide reductase (Ahp) is the major scavenger of endogenous H(2)O(2) in Escherichia coli. Here, we show that aerobically grown Br...

Escherichia coli generates about 14 microM hydrogen peroxide (H(2)O(2)) per s when it grows exponentially in glucose medium. The steady-state intracellular concentration of H(2)O(2) depends on the rates at which this H(2)O(2) is dissipated by scavenging enzymes and by efflux from the cell. The rates of H(2)O(2) degradation by the two major scavenging enzymes, alkyl hydroperoxide reductase and c...

From Xanthomonas campestris pv. phaseoli, we have isolated by two independent methods genes involved in peroxide detoxification (ahpC and ahpF), a gene involved in peroxide sensing and transcription regulation (oxyR), and a gene of unknown function (orfX). Amino acid sequence analysis of AhpC, AhpF, and OxyR showed high identity with bacterial homologs. OrfX was a small cysteine-rich protein wi...

The trapping of a sulfenic acid within the fully active C165S mutant of the AhpC peroxidase protein from Salmonella typhimurium was investigated. The electrophilic reagent employed in these studies, 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl), has previously been used to modify thiol, amino, and tyrosine hydroxyl groups in proteins; at neutral pH only cysteinyl residues of AhpC proteins are...

Bbstract Recent developments involving polymer-supported metal complexes as catalysts in oxidation reactions, using dioxygen, hydrogen peroxide, alkyl hydroperoxides, hypochlorite anion and iodosobenzene as oxidants are reviewed. binding of dioxygen, and in catalysis, along with the structurally closely related metallo-phthalocyanines, oxidative polymerization catalysed by polymer-supported cop...

A comparative theoretical study is presented on the formation and fate of α-amino-peroxyl radicals, recently proposed as important intermediates in the aerobic oxidation of amines. After radical abstraction of the weakly bonded αH-atom in the amine substrate, the α-amino-alkyl radical reacts irreversibly with O(2), forming the corresponding α-amino-peroxyl radical. HO(2)˙-elimination from vario...

Bacillus subtilis cells lacking the PerR repressor which regulates transcription of genes encoding oxidative stress protective proteins grew at 30-50% the rate of wild-type cells, and perR cultures accumulated rapidly growing suppressor mutants lacking the catalase whose expression is regulated by PerR. However, perR spores which retained the perR regulated catalase were obtained on plates. The...

Oil-derived products can be subjected to conditions that promote oxidation of their unsaturated components during storage and use. The materials arising during oxidation and subsequent degradation can seriously impair the quality and performance of such products [1, 2]. Thus, oxidative stability is an important issue to face before studying their catalytic reactivity. The fatty acid alkyl chain...