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Calcium destabilizes and causes conformational changes in hyaluronic acid
1Center for Thrombosis and Hemostasis, Lineberger Cancer Research Center, U.N.C. School of Medicine, Chapel Hill.
The American Journal of the Medical Sciences
|July 1, 1989
Summary
Hyaluronic acid's (HA) structure is sensitive to temperature and calcium ions. Calcium significantly reduces HA stability and alters its physical properties, potentially facilitating cell movement.
Area of Science:
- Biochemistry
- Biophysics
- Materials Science
Background:
- Proteoglycans in the extracellular matrix influence cellular and molecular behavior.
- Hyaluronic acid (HA) is a key extracellular matrix component with significant structural properties.
Purpose of the Study:
- To measure the forces stabilizing structured regions of human HA.
- To determine the impact of temperature and calcium ions on HA stability and physical properties.
Main Methods:
- Potentiometric titration to determine the free energy of stability.
- Classical light scattering and viscosity measurements.
- Analysis of HA structure at varying temperatures and CaCl2 concentrations.
Main Results:
- HA secondary structure is most stable at 25°C and destabilizes near 50°C.
- 5 mM CaCl2 reduced HA stability by 30 cal/mole.
- Calcium ions reduced HA's radius of gyration and viscosity, particularly above 3 mM.
Conclusions:
- Hyaluronic acid's physical properties are significantly modulated by calcium ions.
- Cell-secreted calcium may mediate extracellular matrix modification.
- HA's sensitivity to calcium may facilitate cell motility.