Cytochrome P-450 metabolites of arachidonic acid, the epoxyeicosatrienoic acids (EETs) and hydrogen peroxide (H(2)O(2)), are important signaling molecules in the kidney. In renal arteries, EETs cause vasodilation whereas H(2)O(2) causes vasoconstriction. To determine the physiological contribution of H(2)O(2), catalase is used to inactivate H(2)O(2). However, the consequence of catalase action ...

One of the earliest reports on the systemic effects of tumors was made by Brahn (2), who found that the liver catalase activity of human beings with cancer of the rectum, stomach, pancreas, and intestine was very much lower than normal. This systemic phenomenon later was studied extensively by Greenstein et al. (4-8) with the use of a large number and variety of tumor-bearing mice and rats. How...

Catalase, an antioxidant enzyme responsible for degradation of hydrogen peroxide, is protective in many diseases. The amino-acid homocysteine has been suggested to be a pro-oxidant with elevated levels linked to the oxidative stress seen in Alzheimer’s and other diseases. This study shows that homocysteine inhibits the breakdown of hydrogen peroxide by catalase. Physiological concentrations of ...

Catalase is an antioxidant enzyme the activity of which is crucial for the protection against damage caused by reactive oxygen species. The -262C>T polymorphism in the promoter region of catalase gene was found to be associated with altered catalase levels. In this study, peripheral blood mononuclear cells catalase activity was measured after H(2)O(2)-induced oxidative stress. C/T and T/T genot...

Catalase enzyme from red poppy (Papaver rhoeas) plant was immobilized covalently with glutaraldehyde onto chitosan particles. The changes in the kinetic properties of the immobilized and free red poppy catalase were determined. The Km values were found to be 26 and 33 mM for free and immobilized red poppy catalase on chitosan. Furthermore, various characteristics of free and immobilized red pop...

Development of cancer cell resistance against prooxidant drugs limits its potential clinical use. MCF-7 breast cancer cells chronically exposed to ascorbate/menadione became resistant (Resox cells) by increasing mainly catalase activity. Since catalase appears as an anticancer target, the elucidation of mechanisms regulating its expression is an important issue. In MCF-7 and Resox cells, karyot...

In a variety of disorders, endothelial cells are exposed to high levels of oxidants, generated within the cells and/or consequent to local inflammation. In the context of the sensitivity of endothelial cells to oxidant stress, particularly related to H2O2, we have designed a replication deficient recombinant adenovirus containing the human catalase cDNA (AdCL) to transfer the catalase cDNA to t...