5/3 Dr. Nina Isoherranen

Dr. Nina Isoherranen

University of Washington

Friday, May 10, 2024
12:00 Noon
Room 120 – Meyerhoff Chemistry Building
Host: Dr. Kamal Seneviratne

“Towards Quantitative Adductomics: Novel proteomics Methods to Identify and Quantify Unknown Protein Adducts”

Drug and xenobiotic metabolism by cytochrome P450s (CYPs) in the liver can produce electrophilic metabolites that react with cellular nucleophiles including critical proteins. This can cause toxic side effects via formation of covalent protein adducts. Detection and characterization of such adducts is confounded as the mass, proteins and amino acids modified by reactive metabolites are often unknown and multiple metabolic pathways can lead to different protein adducts. Oftentimes reactive metabolites form adducts with multiple proteins, peptides, and amino acid residues. In such a scenario the importance of specific adducts in causing altered protein and cellular function is unknown and novel tools are needed to identify and quantify specific adducts to correlate their formation to specific outcomes. The lecture will focus on the development and application of novel LC-MS/MS based proteomics methods and software tools to identify drug-protein adducts with no prior knowledge of their nature, and the methods developed to assess the relative importance of specific peptide and protein adducts.  The application of the developed methods to the identification of numerous novel protein adducts in human liver CYPs and other proteins in different matrices with increasing complexity will be presented. The approach and results of relative quantification of the adducts identified will be covered together with confirmatory analyses using various proteomics-based methods for adduct characterization.  The work covered shows that the relationship between specific adduct formation and altered catalytic activity in CYP enzymes is more complex than previously thought. The methods presented will be helpful for broader evaluation of drug and toxicant induced human adductome that may have significant consequences to human health.