Format

Send to

Choose Destination
Nitric Oxide. 2019 Jan 30;85:28-34. doi: 10.1016/j.niox.2019.01.014. [Epub ahead of print]

Acceleration of the autoxidation of nitric oxide by proteins.

Author information

1
Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Center for Free Radical and Biomedical Research, Universidad de la República, Igua 4225, CP11400, Montevideo, Uruguay. Electronic address: mmoller@fcien.edu.uy.
2
Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Center for Free Radical and Biomedical Research, Universidad de la República, Igua 4225, CP11400, Montevideo, Uruguay. Electronic address: denicola@fcien.edu.uy.

Abstract

Lipoproteins and lipid membranes accelerate NO autoxidation by increasing local concentration of NO and O2. Although the idea that proteins could also accelerate this reaction was presented some time ago, it was largely criticized and dismissed. Herein the effect of proteins on NO autoxidation rates was studied following NO disappearance with a selective electrode. It was found that human serum albumin (HSA) accelerated NO autoxidation by a factor of 9 per g/mL of protein, much less than previously suggested. The acceleration by HSA was sensitive to pH and significantly decreased at pH lower than 4.5 coincident with the acid structure transition of HSA to a partially unfolded and rigid conformation. Other proteins with different surface hydrophobicity also accelerated NO autoxidation and it was found to depend mostly on the protein size and dynamics. Mathematical simulations were performed to assess the physiological importance of this acceleration. It was calculated that in plasma the autoxidation of NO is accelerated 1.38 times by HSA relative to water alone, but this becomes of little relevance when whole blood is simulated because of the rapid rate of NO consumption by red blood cells.

PMID:
30710694
DOI:
10.1016/j.niox.2019.01.014

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center