title: Identification of Ca2+-stimulated polyphosphoinositide phospholipase C in isolated plant plasma membranes.
abstract: A polyphosphoinositide phospholipase C has been identified in highly purified plasma membranes from shoots and roots of wheat seedlings. The enzyme preferentially hydrolysed phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate and had a different phosphoinositide substrate profile from soluble phospholipase C. The enzyme activity was lower in plasma membranes isolated from light-grown shoots than from dark-grown ones, whereas no differences in activity between plasma membranes from light- and dark-grown roots were seen. Maximum activity of the membrane-bound enzyme was observed around pH 6. It was activated by micromolar concentrations of Ca2+, but not by GTP or GTP analogues. The enzyme may participate in signal transduction over the plant plasma membrane.
authors.affiliation: Department of Biochemistry, Chemical Centre, Lund, Sweden.
authors.forename: P M
authors.initials: PM
authors.lastname: Melin
authors.forename: M
authors.initials: M
authors.lastname: Sommarin
authors.forename: A S
authors.initials: AS
authors.lastname: Sandelius
authors.forename: B
authors.initials: B
authors.lastname: Jergil
mesh_terms: D002118:Calcium / Q000502:physiology; D002462:Cell Membrane / Q000201:enzymology*; D003600:Cytosol / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007295:Inositol Phosphates / Q000502:physiology; D007700:Kinetics; D010716:Phosphatidylinositols / Q000502:physiology*; D014908:Triticum; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D010738:Type C Phospholipases; D002118:Calcium