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Modulation of phospholipase A2 activity in human synovial fluid by cations
A A Fawzy1, R Dobrow, R C Franson
1Department of Biochemistry, Medical College of Virginia, Richmond 23298.
Inflammation
|December 1, 1987
Summary
This study investigated phospholipase A2 (PLA2) activity in arthritis synovial fluid. Monovalent cations like sodium significantly altered PLA2 activity, with optimal conditions found at specific pH and ion concentrations.
Area of Science:
- Biochemistry
- Enzymology
- Rheumatology
Background:
- Phospholipase A2 (PLA2) plays a role in inflammatory processes.
- Synovial fluid analysis can provide insights into joint diseases like arthritis.
Purpose of the Study:
- To measure cell-free, calcium-dependent phospholipase A2 (PLA2) activity in human synovial fluid from arthritis patients.
- To investigate the effects of monovalent and multivalent cations on PLA2 activity.
Main Methods:
- Assayed PLA2 activity in human synovial fluid using a radiolabeled substrate.
- Examined the influence of varying concentrations of NaCl, other monovalent cations, and multivalent cations on PLA2 activity.
- Determined optimal pH and cation concentrations for PLA2 activity.
Main Results:
- PLA2 activity was dose-dependently stimulated and inhibited by NaCl, with maximal stimulation at 150 mM Na+.
- Optimal PLA2 activity occurred at pH 6.5-8.0 with 150 mM Na+ and 4 mM Ca2+.
- No significant difference in PLA2 activity was observed between rheumatoid arthritis and other arthritis types.
Conclusions:
- Monovalent cations, particularly sodium, significantly modulate Ca2+-dependent PLA2 activity in human synovial fluid.
- PLA2 activity in synovial fluid is not significantly different across various arthritis types studied.
- Further research into cation modulation of PLA2 may offer therapeutic targets for arthritis.