UPLC–MS/MS-Based Targeted Proteomics Assay to Evaluate the Relationship between CYP3A2 Expression and Enzymatic Activity

Traditional analytical methods such as western blotting and reverse transcription-polymerase chain reaction only allow semi- quantitative assessments and cannot accurately quantify the expression of the cytochrome P450 (CYP) enzyme. Therefore, the relationship between excess CYP enzyme and enzymatic activity is not been systematically studied yet. In the present study, we developed a new method using ultra-high-performance liquid chromatography (UPLC) mass spectroscopy (MS)/MS and determined the accurate quantification of CYP3A2 in rat liver. The linear range was 0.1329–8.508 ng/mL. The intra- and inter- day precisions and accuracies data fulfilled the acceptance criteria of food and drug association guidelines for bio analytical method validation. We compared the quantitative results with CYP3A2 activity obtained by the cocktail assay. The developed method was successfully used for the quantitative analysis of CYP3A2. It provided a good background for determining the differences in drug metabolism caused by different CYP expression.