Leaf extracts of both Nicotiana tabacum and Nicotiana sylvestris contain multiple forms of catalase (H(2)O(2):H(2)O(2) oxidoreductase, EC 1.11.1.6) which are separable at different pH values by chromatofocusing columns. Marked changes in distribution of these catalases occur during seedling development and leaf maturation. The form of catalase eluting first (peak 1) was predominant during early...

Plant responses to biotic and abiotic stresses are usually accompanied by the release of reactive oxygen species including hydrogen peroxide. Hydrogen peroxide plays a direct role in defense and is involved in many signal transduction pathways that lead to the proliferation of other defenses. Because catalase helps to maintain reactive oxygen homeostasis during biotic and abiotic stress, its ac...

The erythrocytes represent an important source of antioxidant capacity of the blood. Catalase (EC 1.11.1.6.) is one of the enzymatic components of their antioxidant defense system. The objective of this study was to follow erythrocyte catalase (CAT) in 7-, 15-, 21-, 35-, 60- and 90-day-old Wistar rats of both sexes in normoxia and after exposure to intensive acute hypobaric hypoxia. During the ...

Growth of originally aerobic bakers' yeast under conditions of anaerobiosis caused a decrease in the total specific catalatic activity (patent plus cryptic) of one-half per generation. It is concluded that reversion of catalase was a dilution, rather than a destruction, of the intracellular enzyme. However, the specific patent (whole cell) catalase activity remained constant for one or more gen...

There has been considerable discussion on the nature of the chemical configuration of the primary peroxide complexes of the catalases and peroxidases. The simplest hypothesis (l-5)) namely that peroxide complexes are formed in the reaction, is subject to alternative interpretations. For example, it has been postulated that the spectroscopically identifiable reaction product is not a peroxide co...

In previous communications, we considered the kinetics of the catalase-H202 intermediate in coupled oxidations ofthe isolated liver catalase (Chance, 1949) and of the mixed mitochondrial-peroxisomal fraction (Chance & Oshino, 1971). In those cases, it was possible to record the kinetics of formation of the intermediate by H202 pulses, and solve for the H202 concentration. In most ofthe cases, h...

background: using human skin-fibroblast cell line hf2ff, the efficacy of some drugs was evaluated against sulfur mustard (sm) cytotoxicity. the drugs were the sulfhydryl containing molecule including n-acetylcysteine (nac), 2-oxo-thiazolidine-4-carboxylate (otc) and acetaminophen as glutathione (gsh) stimulator pathway. methods: the protective effects of nac (0.1 mm), otc (1.8 mm), and acetamin...

AIMS Oxidative stress plays a crucial role in the pathogenesis of multiple sclerosis (MS). Melatonin has a central role in the modulation of oxidative stress pathways. We aimed to investigate the effect of melatonin on mRNA expression and activity of sirtuin1 (SIRT1) and its target genes, manganese superoxide dismutase (MnSOD), and catalase in peripheral blood mononuclear cells (PBMCs) from MS ...

For over two decades H. VON EULER (3) and his coworkers have studied the relationship of catalase to chlorophyll. In their work they utilized various chlorophyll defective plants including genetic albinos, variegated, chlorotic and etiolated plants. In general, they found a parallelism between chlorophyll content and catalase activity. NAKAMURA (11) working with a number of higher and lower for...

The catalase activity of unwashed preparations containing intact spinach (Spinacia oleracea L.) chloroplasts is inhibited both by cyanide and by azide at concentrations which also cause inhibition of photosynthetic CO(2)- dependent O(2) evolution.Aminotriazole can also be used to inhibit this contaminant catalase, and in this case inhibition of catalase can be achieved at aminotriazole concentr...