The study provides compelling evidence that BRB forms covalent adducts with CYP2D6 cysteine residues, resulting in irreversible enzyme inactivation. Specific cysteine residues, such as Cys443 and Cys296, are proposed as potential adduction sites based on prior literature. Could the authors clarify whether these specific sites were directly identified in this study through experimental validation, such as site-directed mutagenesis or advanced proteomics? If not, are there plans to employ techniques like tandem mass spectrometry or partial proteolysis coupled with high-resolution LC-MS/MS to pinpoint the exact modification sites in future investigations? Furthermore, while the study rules out ROS-mediated pathways using catalase and superoxide dismutase, could the authors elaborate on whether other ROS-related mechanisms or alternative adduction sites were systematically excluded to confirm the proposed metabolic pathway?
