{"title":"香柏蓝对小麦叶片硝酸还原酶活性的抑制作用。","authors":"B A Albassam","doi":"10.1080/15216549800204532","DOIUrl":null,"url":null,"abstract":"<p><p>Cibacron Blue F3GA (CB) inhibited the activities of wheat leaves NADH:nitrate reductase and NADH:cytochrome-c reductase in a time-independent and concentration dependent manner. The methyl viologen:nitrate reductase activity of the enzyme was unaffected by various CB concentrations used in the experiment. Inhibition of NADH:nitrate reductase was of mixed type (partial competitive and pure noncompetitive) with respect to NADH and noncompetitive with respect to nitrate. The estimated inhibition constant (Ki) values were 1 microM for NADH and 8.4 microM for nitrate. The secondary plots of inhibition with respect to NADH, indicated a dissociation constant (KI) of 8.8 microM for the enzyme-NADH-CB complex. This KI being greater than the Ki suggested that the noncompetitive inhibition is predominant over the competitive inhibition at the NADH binding site.</p>","PeriodicalId":8770,"journal":{"name":"Biochemistry and molecular biology international","volume":"46 5","pages":"979-86"},"PeriodicalIF":0.0000,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15216549800204532","citationCount":"4","resultStr":"{\"title\":\"Inhibition of wheat leaves nitrate reductase activity by cibacron blue.\",\"authors\":\"B A Albassam\",\"doi\":\"10.1080/15216549800204532\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Cibacron Blue F3GA (CB) inhibited the activities of wheat leaves NADH:nitrate reductase and NADH:cytochrome-c reductase in a time-independent and concentration dependent manner. The methyl viologen:nitrate reductase activity of the enzyme was unaffected by various CB concentrations used in the experiment. Inhibition of NADH:nitrate reductase was of mixed type (partial competitive and pure noncompetitive) with respect to NADH and noncompetitive with respect to nitrate. The estimated inhibition constant (Ki) values were 1 microM for NADH and 8.4 microM for nitrate. The secondary plots of inhibition with respect to NADH, indicated a dissociation constant (KI) of 8.8 microM for the enzyme-NADH-CB complex. This KI being greater than the Ki suggested that the noncompetitive inhibition is predominant over the competitive inhibition at the NADH binding site.</p>\",\"PeriodicalId\":8770,\"journal\":{\"name\":\"Biochemistry and molecular biology international\",\"volume\":\"46 5\",\"pages\":\"979-86\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1998-12-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1080/15216549800204532\",\"citationCount\":\"4\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Biochemistry and molecular biology international\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1080/15216549800204532\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biochemistry and molecular biology international","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1080/15216549800204532","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Inhibition of wheat leaves nitrate reductase activity by cibacron blue.
Cibacron Blue F3GA (CB) inhibited the activities of wheat leaves NADH:nitrate reductase and NADH:cytochrome-c reductase in a time-independent and concentration dependent manner. The methyl viologen:nitrate reductase activity of the enzyme was unaffected by various CB concentrations used in the experiment. Inhibition of NADH:nitrate reductase was of mixed type (partial competitive and pure noncompetitive) with respect to NADH and noncompetitive with respect to nitrate. The estimated inhibition constant (Ki) values were 1 microM for NADH and 8.4 microM for nitrate. The secondary plots of inhibition with respect to NADH, indicated a dissociation constant (KI) of 8.8 microM for the enzyme-NADH-CB complex. This KI being greater than the Ki suggested that the noncompetitive inhibition is predominant over the competitive inhibition at the NADH binding site.
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