Effect of monolayer surface pressure on the activities of phosphoinositide-specific phospholipase C-beta 1, -gamma 1, and -delta 1

Biochemistry. 1994 Mar 15;33(10):3032-7. doi: 10.1021/bi00176a036.


Three isoforms of phospholipase C, either PLC-beta 1, PLC-gamma 1, or PLC-delta 1, were added to the aqueous subphase beneath phospholipid monolayers formed at an air-solution interface, and the initial rate of hydrolysis of phosphatidylinositol 4,5-bisphosphate was measured after addition of 10 microM free Ca2+. The monolayers were formed from mixtures of phosphatidylcholine (65% PC), phosphatidylserine (33% PS), and phosphatidylinositol 4,5-biphosphate (2% PIP2). Increasing the surface pressure of the monolayer, pi, from 15 to 25 mN/m decreases the rate of hydrolysis 16-, 13-, and 5-fold for PLC-beta 1, PLC-gamma 1, and PLC-delta 1, respectively. The simplest interpretation of these results is that a portion of each of the enzymes of area Ap must insert into the monolayer, doing work pi Ap, prior to hydrolysis of PIP2; binding studies with simple model compounds of known cross-sectional area are consistent with this interpretation. Removing the monovalent acidic lipid PS from the monolayer decreases the initial rates of hydrolysis of PIP2 about 3-fold for each PLC isoform, which suggests that negative electrostatic surface potentials increase the PLC activity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Brain / enzymology
  • Cattle
  • Isoenzymes / isolation & purification
  • Isoenzymes / metabolism*
  • Kinetics
  • Liposomes
  • Phosphatidylcholines / pharmacology
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositol Diacylglycerol-Lyase
  • Phosphatidylinositol Phosphates / pharmacology
  • Phosphatidylserines / pharmacology
  • Phosphoric Diester Hydrolases / isolation & purification
  • Phosphoric Diester Hydrolases / metabolism*
  • Pressure
  • Surface Properties


  • Isoenzymes
  • Liposomes
  • Phosphatidylcholines
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositol Phosphates
  • Phosphatidylserines
  • Phosphoric Diester Hydrolases
  • Phosphatidylinositol Diacylglycerol-Lyase