Nitrosative stress has been linked to many neurodegenerative disorders including Alzheimer’s and Parkinson’s diseases. The concentrations of superoxide and nitric oxide, the two compounds that react to form peroxynitrite (ONOO-), are typically tightly controlled under physiological conditions. However, when ONOO- is overproduced, it can react with the tyrosine residues of proteins, leading to the formation of 3-nitrotyrosine. Nitrotyrosine has been used as a biomarker of oxidative stress in vivo. A method for the separation and detection of tyrosine and tyrosine-containing peptides and their nitrated products by capillary electrophoresis with UV detection was developed. The analytes of interest included tyrosine (Y), 3-nitrotyrosine (NO2Y), 3-aminotyrosine (NH2Y), and the peptides AY, A(NO2Y), AYL, A(NO2Y)L, FSAYLER, and FSA(NO2Y)LER. The effects of buffer type, pH, concentration, and surfactant concentration on the separation were investigated. This method was then used to investigate the reaction of peroxynitrite with tyrosine and tyrosine-containing peptides. Peroxynitrite was synthesized using acidified hydrogen peroxide and sodium nitrite. The degradation of ONOOH over time was studied by varying the time between mixing of reagents and the addition of sodium hydroxide to quench the reaction and stabilize the peroxynitrite in its anionic form. The peroxynitrite was monitored using a previously optimized, reverse polarity CE separation with visible detection. Similarly, the time between ONOO- formation and the addition of tyrosine and tyrosine-containing peptides was varied, and the reaction products separated using the previously optimized method.

Separation and detection of reaction products of tyrosine and tyrosine-containing peptides with peroxynitrite using capillary electrophoresis with UV detection

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.