Polyphosphoinositide phospholipase C in wheat root plasma membranes. Partial purification and characterization

Biochim Biophys Acta. 1992 Jan 24;1123(2):163-9. doi: 10.1016/0005-2760(92)90107-7.

Abstract

The effect of various detergents on polyphosphoinositide-specific phospholipase C activity in highly purified wheat root plasma membrane vesicles was examined. The plasma membrane-bound enzyme was solubilized in octylglucoside and purified 25-fold by hydroxylapatite and ion-exchange chromatography. The purified enzyme catalyzed the hydrolysis of phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2) with specific activities of 5 and 10 mumol/min per mg protein, respectively. Phosphatidylinositol (PI) was not a substrate. Optimum activity was between pH 6-7 (PIP) and pH 6-6.5 (PIP2). The enzyme was dependent on micromolar concentrations of Ca2+ for activity, and millimolar Mg2+ further increased the activity. Other divalent cations (4 mM Ca2+, Mn2+ and Co2+) inhibited (PIP2 as substrate) or enhanced (PIP as substrate) phospholipase C activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / pharmacology
  • Catalysis
  • Cell Membrane / drug effects
  • Cell Membrane / enzymology
  • Detergents
  • Hydrolysis
  • Magnesium Chloride / pharmacology
  • Phosphoinositide Phospholipase C
  • Phosphoric Diester Hydrolases / chemistry
  • Phosphoric Diester Hydrolases / isolation & purification*
  • Substrate Specificity
  • Triticum / drug effects
  • Triticum / enzymology*

Substances

  • Detergents
  • Magnesium Chloride
  • Phosphoric Diester Hydrolases
  • Phosphoinositide Phospholipase C
  • Calcium