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Characterization of reactions catalysed by yeast phosphatidylinositol synthase
Author(s) -
Klezovitch Olga,
Brandenburger Yves,
Geindre Michèle,
Deshusses Jacques
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80598-o
Subject(s) - phosphatidylinositol , inositol , diacylglycerol kinase , chemistry , biochemistry , atp synthase , enzyme , yeast , signal transduction , protein kinase c , receptor
The nature of reactions catalysed by yeast phosphatidylinositol synthase expressed in E. coli has been investigated. The single enzyme is shown to carry both CDP‐diacylglycerol‐dependent incorporation of inositol into phosphatidylinositol ( K m for inositol of 0.090 mM) and a CDP‐diacylglycerol‐independent exchange reaction between phosphatidylinositol and inositol ( K m for inositol of 0.066 mM). The exchange reaction and reversal of phosphatidylinositol synthase were both stimulated by CMP, but had different optimum pH and requirements for substrates. These results suggest that CMP‐stimulated exchange and CMP‐dependent reverse reactions are distinct processes catalysed by the same enzyme. phosphatidylinositol synthase.