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Diffusion of nitric oxide into low density lipoprotein.
Ana Denicola1, Carlos Batthyány, Eduardo Lissi
1Department of Physical Biochemistry, Facultad de Ciencias, Universidad de la República, 11400 Montevideo, Uruguay.
The Journal of Biological Chemistry
|November 2, 2001
Summary
Nitric oxide (NO) readily diffuses into low-density lipoprotein (LDL) particles, acting as an effective antioxidant. This study confirms NO
Area of Science:
- Biochemistry
- Cardiovascular Research
- Oxidative Stress
Background:
- Atherosclerosis involves low-density lipoprotein (LDL) oxidation.
- Nitric oxide (NO) inhibits LDL oxidation by scavenging radicals.
- Understanding NO diffusion in LDL is crucial for its antioxidant role.
Purpose of the Study:
- To investigate the diffusion of nitric oxide (NO) into LDL particles.
- To determine the rate and efficiency of NO penetration into LDL's surface and core.
- To affirm NO's role as a lipophilic antioxidant within LDL.
Main Methods:
- Utilized fluorescence quenching of pyrene derivatives (PMTMA and PMChO) to track NO diffusion.
- Incorporated probes at LDL surface and core to assess depth-specific penetration.
- Measured apparent second-order rate quenching constants (k(NO)) and diffusion coefficients (D(')NO).
Main Results:
- PMTMA and PMChO successfully localized to LDL surface and core, respectively.
- NO demonstrated facile diffusion into both native and oxidized LDL.
- Apparent diffusion coefficient of NO in LDL was found to be 2 x 10(-5) cm(2) s(-1).
Conclusions:
- NO readily diffuses through the LDL particle, accessing its hydrophobic lipid core.
- NO functions as a significant lipophilic antioxidant, protecting LDL from oxidation.
- These findings support NO's protective role against atherosclerosis development.