{"title":"磷脂酰肌醇特异性磷脂酶C释放后山羊肝质膜碱性磷酸酶活性增加。","authors":"Deepali Kothekar, Atmaram Bandivdekar, Debjani Dasgupta","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>Mammalian alkaline phosphatase (ALP) is attached to the plasma membrane by a unique glycosylphosphatidylinositol (GPI) anchor. The influence of such a complex anchoring device on the enzyme function is not fully understood. Here, we report the effect of cleavage of the GPI anchor on the activity of goat liver plasma membrane ALP (GLPM-ALP). Phosphatidylinositol-specific phospholipase C (PI-PLC) purified from Bacillus cereus was used for the cleavage of the GPI anchor (delipidation) and hence for release of ALP from the membrane. Detergents--octyl-beta-D-glucopyranoside (OG) and triton X100 (TX100) were also used for solubilization of ALP from the membrane. Resistance to solubilization by TX100 suggested the association of GPI-ALP with lipid rafts. Solubilization of GLPM-ALP with OG had no effect on the enzyme activity; however, delipidation with PI-PLC resulted in enhanced ALP activity. Kinetic analysis showed catalytic activation of PI-PLC-treated GLPM-ALP with an increase in V(max) (35%) without a significant change in K(m). Moreover, this change in Vmax was observed to be independent of pH and buffer. The results suggested the implication of GPI anchor in modulating the catalytic property of GLPM-ALP, thus indicating the role of this special anchoring structure in the enzyme regulation.</p>","PeriodicalId":13281,"journal":{"name":"Indian journal of biochemistry & biophysics","volume":"51 4","pages":"263-70"},"PeriodicalIF":1.5000,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Increased activity of goat liver plasma membrane alkaline phosphatase upon release by phosphatidylinositol-specific phospholipase C.\",\"authors\":\"Deepali Kothekar, Atmaram Bandivdekar, Debjani Dasgupta\",\"doi\":\"\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Mammalian alkaline phosphatase (ALP) is attached to the plasma membrane by a unique glycosylphosphatidylinositol (GPI) anchor. The influence of such a complex anchoring device on the enzyme function is not fully understood. Here, we report the effect of cleavage of the GPI anchor on the activity of goat liver plasma membrane ALP (GLPM-ALP). Phosphatidylinositol-specific phospholipase C (PI-PLC) purified from Bacillus cereus was used for the cleavage of the GPI anchor (delipidation) and hence for release of ALP from the membrane. Detergents--octyl-beta-D-glucopyranoside (OG) and triton X100 (TX100) were also used for solubilization of ALP from the membrane. Resistance to solubilization by TX100 suggested the association of GPI-ALP with lipid rafts. Solubilization of GLPM-ALP with OG had no effect on the enzyme activity; however, delipidation with PI-PLC resulted in enhanced ALP activity. Kinetic analysis showed catalytic activation of PI-PLC-treated GLPM-ALP with an increase in V(max) (35%) without a significant change in K(m). Moreover, this change in Vmax was observed to be independent of pH and buffer. The results suggested the implication of GPI anchor in modulating the catalytic property of GLPM-ALP, thus indicating the role of this special anchoring structure in the enzyme regulation.</p>\",\"PeriodicalId\":13281,\"journal\":{\"name\":\"Indian journal of biochemistry & biophysics\",\"volume\":\"51 4\",\"pages\":\"263-70\"},\"PeriodicalIF\":1.5000,\"publicationDate\":\"2014-08-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Indian journal of biochemistry & biophysics\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"\",\"RegionNum\":4,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"BIOCHEMISTRY & MOLECULAR BIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Indian journal of biochemistry & biophysics","FirstCategoryId":"99","ListUrlMain":"","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
Increased activity of goat liver plasma membrane alkaline phosphatase upon release by phosphatidylinositol-specific phospholipase C.
Mammalian alkaline phosphatase (ALP) is attached to the plasma membrane by a unique glycosylphosphatidylinositol (GPI) anchor. The influence of such a complex anchoring device on the enzyme function is not fully understood. Here, we report the effect of cleavage of the GPI anchor on the activity of goat liver plasma membrane ALP (GLPM-ALP). Phosphatidylinositol-specific phospholipase C (PI-PLC) purified from Bacillus cereus was used for the cleavage of the GPI anchor (delipidation) and hence for release of ALP from the membrane. Detergents--octyl-beta-D-glucopyranoside (OG) and triton X100 (TX100) were also used for solubilization of ALP from the membrane. Resistance to solubilization by TX100 suggested the association of GPI-ALP with lipid rafts. Solubilization of GLPM-ALP with OG had no effect on the enzyme activity; however, delipidation with PI-PLC resulted in enhanced ALP activity. Kinetic analysis showed catalytic activation of PI-PLC-treated GLPM-ALP with an increase in V(max) (35%) without a significant change in K(m). Moreover, this change in Vmax was observed to be independent of pH and buffer. The results suggested the implication of GPI anchor in modulating the catalytic property of GLPM-ALP, thus indicating the role of this special anchoring structure in the enzyme regulation.
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