{"title":"Pressure variation of enzymatic reaction rates: IV. Xanthine oxidase and superoxide dismutase.","authors":"E Morild, J E Olmheim","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>Effect of pressure on activities of O-(2)-producing enzyme xanthine oxidase (XO) and O-(2)-scavenging enzyme superoxide dismutase (SOD) has been investigated to 1000 bar. Methods used included spectrophotometric determinations of inhibition by SOD of O-(2)-induced reduction of cytochrome c and oxidation of ascorbic acids. It was found that (1) pressure increases XO activity, the activation volume being delta V not equal to = -45 +/- 5 cm3/mol; and (2) pressure decreases SOD activity, the activation volume being delta V not equal to = 30 +/- 5 cm3/mol. Under the conditions of these experiments, pressure therefore favors an increase in O-(2) activity. This may lead to increased cell damage in organisms in high-pressure situations even if oxygen concentration is held constant.</p>","PeriodicalId":20124,"journal":{"name":"Physiological chemistry and physics","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physiological chemistry and physics","FirstCategoryId":"1085","ListUrlMain":"","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Effect of pressure on activities of O-(2)-producing enzyme xanthine oxidase (XO) and O-(2)-scavenging enzyme superoxide dismutase (SOD) has been investigated to 1000 bar. Methods used included spectrophotometric determinations of inhibition by SOD of O-(2)-induced reduction of cytochrome c and oxidation of ascorbic acids. It was found that (1) pressure increases XO activity, the activation volume being delta V not equal to = -45 +/- 5 cm3/mol; and (2) pressure decreases SOD activity, the activation volume being delta V not equal to = 30 +/- 5 cm3/mol. Under the conditions of these experiments, pressure therefore favors an increase in O-(2) activity. This may lead to increased cell damage in organisms in high-pressure situations even if oxygen concentration is held constant.
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