Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prolonged use of contact lenses (for 14 days) evoked an imbalance between the activity of xanthine oxidase (an enzyme belonging to reactive oxygen species-generating oxidases) and catalase (an enzyme belonging to reactive oxygen species-scavenging oxidases) in the corneal epithelium of rabbits. The activity of catalase decreased, while xanthine oxidase activity was very high. Of other enzymes studied in the corneal epithelium, the activities of xanthine oxidoreductase, glucoso-6-phosphate dehydrogenase and succinate dehydrogenase were decreased. In contrast, the activities of lactate dehydrogenase and lysosomal hydrolases (acid beta-galactosidase, dipeptidyl peptidase II) were increased and appeared in animals sacrificed immediately after contact lens removal. In rabbits sacrificed later (after 1 h), an additional increase of lactate dehydrogenase and lysosomal hydrolase activities developed in the superficial layers of the corneal epithelium. Catalase supplementation during use of contact lenses prevented both the significant decrease of catalase activity in the corneal epithelium and the development of additional epithelial damage. In contrast, topical treatment with 3-aminotriazole (an inhibitor of catalase) resulted in the nearly complete loss of catalase activity in the corneal epithelium and the appearance of more serious epithelial damage. We conclude that ROS generated by xanthine oxidase induce additional damage of the corneal epithelium related to the use of contact lenses.
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PMID:Reactive oxygen species (ROS) generated by xanthine oxidase in the corneal epithelium and their potential participation in the damage of the corneal epithelium after prolonged use of contact lenses in rabbits. 958 28

The activities of superoxide dismutase, glutathione peroxidase (GPX) and catalase--the enzymatic scavengers of reactive oxygen species and the activities of xanthine oxidoreductase and xanthine oxidase, an enzyme known to generate reactive oxygen species, were studied in the corneas of normal rabbit eyes of various ages (1 month--young eyes; 4-9.5 months--young adult eyes; 2.0-2.75 years--middle aged eyes; 3.0-5.0 years--aged eyes). The activities of GPX, superoxide dismutase, xanthine oxidoreductase and xanthine oxidase were investigated biochemically in the scraped corneal epithelium. Catalase activity was detected histochemically in the corneal epithelium and endothelium. The results show that young corneas revealed lower activities of all the antioxidant enzymes investigated than did young adult corneas, in which enzymatic activities reached their maximum. In middle-aged corneas, GPX and catalase activities remained approximately at the same levels as seen in young adult corneas, whereas superoxide dismutase activity was decreased. In aged corneas, the activities of all antioxidant enzymes were dramatically decreased or even lost (catalase activity in the corneal endothelium). In contrast, xanthine oxidoreductase activity only slightly decreased with age and the xanthine oxidase proportion of total xanthine oxidoreductase remained unchanged. GPX, superoxide dismutase and catalase are important antioxidant enzymes protecting the cornea against the oxidative damage. Because the activities of these enzymes are lower in young animals and greatly reduced in aged animals, it is suggested that young and particularly aged corneas might be more susceptible to oxidative stress than are young adult corneas. This presumption is supported by the fact that the activities of prooxidant enzymes (xanthine oxidoreductase/xanthine oxidase) are only slightly decreased in aged corneas as compared to young adult corneas so that some imbalance between antioxidant and prooxidant enzymes exists already in the normal aged corneas.
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PMID:Age-related changes in superoxide dismutase, glutathione peroxidase, catalase and xanthine oxidoreductase/xanthine oxidase activities in the rabbit cornea. 1550 Oct 24

Reactive oxygen species (ROS) generated by xanthine oxidoreductase (XOR) were toxic to B lymphoma-derived Raji cells (positive for 8A monoclonal antibody, mAb). The sensitivity of these malignant cells to the hypoxanthine/XOR system was higher than that observed in peripheral human lymphocytes. The understanding of the mechanisms of cytotoxicity induced by XOR-produced ROS is essential in view of a possible clinical application. Cell death mostly had the feature of apoptosis and post-apoptotic necrosis and depended on the activity of XOR. Catalase, but not superoxide dismutase, protected cells from the toxicity of XOR, thus indicating that cell damage depended on the production of hydrogen peroxide. The toxicity of ROS was selectively targeted to malignant Raji cells by antibody-XOR conjugation, either directly, with an 8A-XOR conjugate, or indirectly, with an 8A mAb plus an anti-mouse IgG-XOR. Both direct and indirect immunotoxins induced apoptotic death to target cells in a dose-dependent manner. These conjugates showed no aspecific cytotoxicity in conditions very similar to the ex vivo treatment of cell suspension for bone marrow transplantation. Moreover, the prevalence of apoptotic death over necrosis may reduce the in vivo inflammatory response and its local and systemic consequences, thus becoming relevant in the construction of immunotoxins with therapeutic potential.
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PMID:Toxicity of xanthine oxidoreductase to malignant B lymphocytes. 1660 26