Thermodynamic properties of the cholesterol transfer reaction from liposomes to cytochrome P450scc: an enthalpy-entropy compensation effect

Biochem Biophys Res Commun. 1984 Feb 14;118(3):877-84. doi: 10.1016/0006-291x(84)91477-3.

Abstract

We have investigated the thermodynamic properties of the cholesterol transfer reaction from various types of liposomes to purified steroid-free cytochrome P450scc. From the results of temperature effect on the reaction, we obtained delta G+, delta H+, and delta S+ values for the reaction with various phosphatidylcholine vesicles containing different fatty acyl chains. The plots of delta H+ against delta S+, and delta G+ against delta H+ both reveal that an enthalpy-entropy compensation effect was seen in a series of phospholipid and micellar media of cholesterol. Our beta-value of 420 degrees K is unusually high among reported values for biochemical reactions.

Publication types

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

MeSH terms

  • Adrenal Cortex / enzymology
  • Animals
  • Cattle
  • Cholesterol / metabolism*
  • Cytochrome P-450 Enzyme System / metabolism*
  • Fatty Acids / metabolism
  • Kinetics
  • Liposomes / metabolism*
  • Micelles
  • Phosphatidylcholines / metabolism
  • Thermodynamics*

Substances

  • Fatty Acids
  • Liposomes
  • Micelles
  • Phosphatidylcholines
  • Cytochrome P-450 Enzyme System
  • Cholesterol