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)

The mechanism for the damage to the alanine-preferring amino acid transport system (A system) of guinea pig intestinal brush border membrane vesicles induced by active oxygen species was studied in vitro. The transport activity of L-proline, which is a model amino acid for the A system, and the tryptophan fluorescence intensity of intestinal brush border membrane vesicles were decreased, and lipid peroxidation of these membrane vesicles was induced by ultraviolet irradiation, which generated active oxygen species. Thiourea (hydroxyl radical scavenger) protected L-proline transport activity and tryptophan fluorescence intensity of intestinal brush border membrane vesicles and also inhibited lipid peroxidation in these membrane vesicles in the presence of active oxygen radicals. alpha-Tocopherol (singlet oxygen radical scavenger) inhibited lipid peroxidation of intestinal brush border membrane vesicles but protected neither L-proline transport activity nor tryptophan fluorescence intensity in these membrane vesicles in the presence of active oxygen radicals. Catalase and superoxide dismutase showed no protective effect on L-proline transport activity, tryptophan fluorescence intensity, or lipid peroxide formation in intestinal brush border membrane vesicles in the presence of active oxygen radicals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Amino acid transport system of the guinea pig small intestine is injured by hydroxyl radicals. 838 54

A comprehensive comparison of antioxidant defenses in the dermis and epidermis and their response to exposure to ultraviolet (UV) irradiation has not previously been attempted. In this study, enzymic and non-enzymic antioxidants in epidermis and dermis of hairless mice were compared. Enzyme activities are presented both as units/gram of skin and units/milligram of protein; arguments are presented for the superiority of skin wet weight as a reference base. Catalase, glutathione peroxidase, and glutathione reductase (units/gram of skin) were higher in epidermis than dermis by 49%, 86%, and 74%, respectively. Superoxide dismutase did not follow this pattern. Lipophilic antioxidants (alpha-tocopherol, ubiquinol 9, and ubiquinone 9) and hydrophilic antioxidants (ascorbic acid, dehydroascorbic acid, and glutathione) were 24-95% higher in epidermis than in dermis. In contrast, oxidized glutathione was 60% lower in epidermis than in dermis. Mice were irradiated with solar light to examine the response of these cutaneous layers to UV irradiation. After irradiation with 25 J/cm2 (UVA + UVB, from a solar simulator), 10 times the minimum erythemal dose, epidermal and dermal catalase and superoxide dismutase activities were greatly decreased. alpha-Tocopherol, ubiquinol 9, ubiquinone 9, ascorbic acid, dehydroascorbic acid, and reduced glutathione decreased in both epidermis and dermis by 26-93%. Oxidized glutathione showed a slight, non-significant increase. Because the reduction in total ascorbate and catalase was much more severe in epidermis than dermis, it can be concluded that UV light is more damaging to the antioxidant defenses in the epidermis than in the dermis.
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PMID:Antioxidant defense mechanisms in murine epidermis and dermis and their responses to ultraviolet light. 844 Sep 1