{"title":"牛脑Ins(1,4)P2 1-磷酸酶对Ins(1,4)P2去磷酸化的动力学研究。","authors":"A Delvaux, J E Dumont, C Erneux","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>Ins(1,4)P2 1-phosphatase catalyses the dephosphorylation of Ins(1,4)P2 to Ins(4)P. This enzyme was purified 3000-fold to a specific activity of 10-20 mumol/min/mg protein. Ins(1,4,5)P3 (0.04-1 microM) was not a substrate of the enzyme under conditions where 50% of Ins(1,4)P2 was dephosphorylated. All kinetics of Ins(1,4)P2 1-phosphatase displayed Michaelis-Menten behaviour. Both reaction products, Ins(4)P and phosphate inhibited the enzyme: Ins(4)P was a non-competitive inhibitor (Ki = 59 microM) and phosphate was competitive (Ki = 0.53 mM) with respect to Ins(1,4)P2 as substrate. In contrast, Li+ inhibition was uncompetitive (Ki at 1 mM LiCl was 2.7 mM).</p>","PeriodicalId":77384,"journal":{"name":"Second messengers and phosphoproteins","volume":"12 5-6","pages":"281-8"},"PeriodicalIF":0.0000,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The kinetics of Ins(1,4)P2 dephosphorylation by Ins(1,4)P2 1-phosphatase in bovine brain.\",\"authors\":\"A Delvaux, J E Dumont, C Erneux\",\"doi\":\"\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Ins(1,4)P2 1-phosphatase catalyses the dephosphorylation of Ins(1,4)P2 to Ins(4)P. This enzyme was purified 3000-fold to a specific activity of 10-20 mumol/min/mg protein. Ins(1,4,5)P3 (0.04-1 microM) was not a substrate of the enzyme under conditions where 50% of Ins(1,4)P2 was dephosphorylated. All kinetics of Ins(1,4)P2 1-phosphatase displayed Michaelis-Menten behaviour. Both reaction products, Ins(4)P and phosphate inhibited the enzyme: Ins(4)P was a non-competitive inhibitor (Ki = 59 microM) and phosphate was competitive (Ki = 0.53 mM) with respect to Ins(1,4)P2 as substrate. In contrast, Li+ inhibition was uncompetitive (Ki at 1 mM LiCl was 2.7 mM).</p>\",\"PeriodicalId\":77384,\"journal\":{\"name\":\"Second messengers and phosphoproteins\",\"volume\":\"12 5-6\",\"pages\":\"281-8\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1988-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Second messengers and phosphoproteins\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Second messengers and phosphoproteins","FirstCategoryId":"1085","ListUrlMain":"","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
The kinetics of Ins(1,4)P2 dephosphorylation by Ins(1,4)P2 1-phosphatase in bovine brain.
Ins(1,4)P2 1-phosphatase catalyses the dephosphorylation of Ins(1,4)P2 to Ins(4)P. This enzyme was purified 3000-fold to a specific activity of 10-20 mumol/min/mg protein. Ins(1,4,5)P3 (0.04-1 microM) was not a substrate of the enzyme under conditions where 50% of Ins(1,4)P2 was dephosphorylated. All kinetics of Ins(1,4)P2 1-phosphatase displayed Michaelis-Menten behaviour. Both reaction products, Ins(4)P and phosphate inhibited the enzyme: Ins(4)P was a non-competitive inhibitor (Ki = 59 microM) and phosphate was competitive (Ki = 0.53 mM) with respect to Ins(1,4)P2 as substrate. In contrast, Li+ inhibition was uncompetitive (Ki at 1 mM LiCl was 2.7 mM).
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