Alkyl hydroperoxide reductase subunit C (AhpC) is the catalytic subunit responsible for alkyl peroxide metabolism. A Xanthomonas ahpC mutant was constructed. The mutant had increased sensitivity to organic peroxide killing, but was unexpectedly hyperresistant to H(2)O(2) killing. Analysis of peroxide detoxification enzymes in this mutant revealed differential alteration in catalase activities i...

The reactions of the fungal enzymes Arthromyces ramosus peroxidase (ARP) and Phanerochaete chrysosporium lignin peroxidase (LiP) with hydrogen peroxide (H(2)O(2)) have been studied. Both enzymes exhibited catalase activity with hyperbolic H(2)O(2) concentration dependence (K(m) approximately 8-10 mm, k(cat) approximately 1-3 s(-1)). The catalase and peroxidase activities of LiP were inhibited w...

Bernhard Epping, Alexander P. Hansen and Peter Martin Institut für Pflanzenernährung (330), Fruwirthstr. 20, Universität Hohenheim, 70593 Stuttgart, Bundesrepublik Deutschland Z. Naturforsch. 50 c, 543-551 (1995); received March 15/May 2, 1995 Oxygen Derivates, Phaseolus vulgaris L.. Rhizobium leguminosarum, Rhizobium tropici, Symbiotic Effectivity Nodules of Rhizobium leguminosarum bv. phaseol...

The heat-labile T class of mycobacterial catalase exhibits peroxidase activity with some substrates. Most species of mycobacteria produce T-catalase, which is serologically characterized by a combination of shared epitopes and unique, species-specific epitopes. Antibodies to T-catalases from Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare have been cross absorb...

Strong antioxidant activity of Pelargonium graveolens is well known. The question addressed in this study was whether different concentrations of exogenous ascorbic acid (AsA) and iron (Fe) were able to influence antioxidant activity and total phenol content (TPC) of geranium. Thus, three levels of Fe (0, 20 and 40 µM) and three levels of AsA (0, 1 and 2 mM) in nutrient solution were c...

The chronic effect of environmental methomyl on the antioxidant system in testis Nile tilapia (Oreochromis niloticus) and its recovery pattern was investigated. Tilapia were exposed to sublethal concentrations 0.2, 2, 20 200 ?gL?1 for 30 days thereafter moved methomyl-free water 18 days. Antioxidant levels testis, including glutathione peroxidase, catalase, glutathione-S-transferase, reductase,...

Rat liver mitochondria are much more susceptible to protein oxidation induced by paraquat than plant mitochondria. The unsaturated index and the peroxidizability index are higher in rat than in potato tuber. The levels of superoxide dismutase and glutathione reductase are concurrent with the different sensitivities to paraquat, with higher activities in plant mitochondria. However, glutathione ...

It has been claimed that the sole H(2)O(2)-scavenging system in the cyanobacterium Synechococcus sp. PCC 7942 is a cytosolic catalase-peroxidase. We have measured in vivo activity of a light-dependent peroxidase in Synechococcus sp. PCC 7942 and UTEX 625. The addition of small amounts of H(2)O(2) (2.5 microM) to illuminated cells caused photochemical quenching (qP) of chlorophyll fluorescence t...

Effect of hydroalcoholic extract T. bispinosa (TB) was studied on fluorescence product and biochemical parameter like lipid peroxidation, catalase activity and glutathione peroxidase activity in the brain of female albino mice. Ageing was accelerated by the treatment of 0.5 ml 5% D-galactose for 15 days. This resulted in increased fluorescence product, increase lipid peroxidation and decrease a...