Ascorbate Free Radical Reductase Activity in Vertebrate Lenses of Certain Species
| Autor: | Mikako Oka, Masayasu Bando, Makoto Takehana, Hajime Obazawa, Shuji Matsukura |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Antioxidant
Swine medicine.medical_treatment Guinea Pigs Reductase Antioxidants Species Specificity Diaphorase Lens Crystalline medicine Animals NADH NADPH Oxidoreductases Rats Wistar Dihydrolipoamide Dehydrogenase chemistry.chemical_classification Rana catesbeiana Dihydrolipoamide dehydrogenase Lagomorpha biology General Medicine Ascorbic acid biology.organism_classification Enzyme assay Rats Ophthalmology Enzyme Solubility chemistry Biochemistry Vertebrates biology.protein Cattle Rabbits |
| Zdroj: | Japanese Journal of Ophthalmology. 45:233-239 |
| ISSN: | 0021-5155 |
| DOI: | 10.1016/s0021-5155(00)00385-3 |
| Popis: | Purpose: To clarify the function of ascorbate free radical (AFR) reductase in the lens antioxidation mechanism, we investigated the difference among species in AFR reductase activity in different vertebrate lenses.Materials and Methods: Soluble and insoluble fractions were prepared from the lenses of frogs, guinea pigs, rats, rabbits, pigs, and calves. AFR reductase and diaphorase activity of each fraction was determined.Results: AFR reductase activity in the lens soluble fraction was the highest in frogs. That of guinea pigs and rabbits was at the next level; there was only a little activity in rats and pigs, and none was detected in calves. Membrane-bound AFR reductase in the lens insoluble fraction was extracted by 0.3% Triton X-100. The membrane-bound enzyme activity was almost at the same level in frogs, rats, rabbits, and calves, and a little higher in guinea pigs and pigs. However, such species-specificity of AFR reductase activity as in the soluble fraction was not observed in 0.3% Triton X-100 extracts. Diaphorase activity was 3 to 9 times as much as AFR reductase activity in the soluble fractions of frogs, guinea pigs, and rabbits, but in 0.3% Triton X-100 extracts of all vertebrate species used, it was very high, 108 to 311 times the AFR reductase activity.Conclusion: These results suggest that the lens soluble and membrane-bound AFR reductases are individual enzyme molecules and have different anti-oxidative functions. The lenses of frogs, guinea pigs, and rabbits contain a near-ultraviolet (UV) light absorbing compound, reduced pyridine nucleotide at a high concentration. Therefore, the soluble AFR reductase activity may be high in the vertebrate lenses with a near-UV light filter, and enhance the antiphotoxidation of ascorbic acid. |
| Databáze: | OpenAIRE |
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