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A neutral phospholipase D activity from rat brain synaptic plasma membranes. Identification and partial
V Chalifa1, H Möhn, M Liscovitch
1Department of Hormone Research, Weizmann Institute of Science, Rehovot, Israel.
The Journal of Biological Chemistry
|October 15, 1990
Summary
Researchers identified a neutral phospholipase D (PLD) in rat brain synaptic membranes. This enzyme, crucial for signal transduction, requires sodium oleate and Mg2+ for optimal activity.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- Phospholipase D (PLD) activation is rapid upon cell stimulation.
- PLD is hypothesized to be involved in signal transduction across the plasma membrane.
Purpose of the Study:
- To identify and characterize a neutral PLD activity in purified rat brain synaptic plasma membranes.
- To determine the in vitro conditions for assaying synaptic membrane PLD activity.
Main Methods:
- Assayed catalytic activity using exogenous [3H]phosphatidylcholine.
- Measured production of [3H]phosphatidic acid and [3H]phosphatidylethanol.
- Investigated the effects of pH, metal ions (Mg2+, Ca2+), and ethanol concentrations.
Main Results:
- Identified a neutral PLD activity with optimal activity at pH 7.2.
- Enzyme activity was dependent on sodium oleate and strongly activated by Mg2+.
- Ca2+ showed mixed effects, stimulating at low concentrations and inhibiting at high concentrations.
- Ethanol concentration influenced the balance between phosphatidic acid and phosphatidylethanol production, indicating competing hydrolase and transferase activities.
Conclusions:
- Characterized the kinetic properties and cofactor requirements of rat brain synaptic membrane PLD.
- The findings provide insights into the role of neutral PLD in neuronal signal transduction.
- Discussed the relationship between this neutral PLD and other identified PLD activities.