Ethanol increases affinity of protein kinase C for phosphatidylserine
Protein kinase C is a calcium-dependent enzyme that requires phospholipid for its activation. It is present in relatively high concentration in the brain and may be involved in neuronal function. The present experiments test whether the membrane disorder induced by ethanol affects the activity of kinase C by changing its interaction with membrane lipid. Fractions rich in kinase C were purified from rat brain cytosol by DEAE-cellulose chromatography and Sephadex G-200 gel filtration. Enzyme activity was assayed by measuring the phosphorylation of histone H1. As expected, phosphatidylserine activated the enzyme, and the stimulation was further increased by the addition of calcium and/or diacylglycerol. At low concentration of free calcium (0.5-1..mu..M), ethanol (800 mM0 enhanced kinase C activity if the presence of phospholipid. similar results were observed in the absence of calcium. Double reciprocal plots of the data showed that ethanol increased the affinity of the enzyme for phosphatidylserine without affecting the V/sub max. The stimulation of kinase C activity by ethanol was not observed at high calcium concentrations. These experiments suggest that ethanol may activated protein kinase C at physiological levels of calcium by facilitating its transfer into the hydrophobic membrane environment.
- Research Organization:
- Stanford Univ., School of Medicine, CA
- OSTI ID:
- 5316477
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ETHANOL
BIOLOGICAL EFFECTS
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
AFFINITY
BRAIN
CALCIUM
CELL MEMBRANES
CHROMATOGRAPHY
FILTRATION
PHOSPHOLIPIDS
PHOSPHORYLATION
RATS
SERINE
ALCOHOLS
ALKALINE EARTH METALS
AMINO ACIDS
ANIMALS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
ELEMENTS
ENZYMES
ESTERS
HYDROXY ACIDS
HYDROXY COMPOUNDS
LIPIDS
MAMMALS
MEMBRANES
METALS
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
PHOSPHORUS-GROUP TRANSFERASES
RODENTS
SEPARATION PROCESSES
TRANSFERASES
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)