[Proteomic study on effect of tangcao pill on microsome CYP450]

Tangcao pill is commonly applied in adjuvant and even alternative therapy for patients with AIDS. However, the herb contains complex ingredients, but with unknown effect against anti-HIV drug and unknown function. Because CYP450 emzyme is the main metabolic enzymes of the drug, it is of important significance to study the regulation of CYP450 enzymes before and after the combined administration of Tangcao pill and EFV. Proteomics, due to its high throughout and high sensitivity, has been widely applied in CYP450 enzyme study. In this paper, liver microsomes were separated through differential centrifugation. Their proteins were separated through SDS-PAGE. The three protein bands that CYP450 enzymes were located were cut and identified by liquid chromatography tandem mass spectrometry. Totally 16 CYP450 isoenzymes were identified. Furthermore, in order to make a quantitative analysis on the effect of tang herb on CYP450 emzyme, the multiple reaction monitoring (MRM) technology based on MS was adopted. The CYP2C11 was selected based on the results of the mass spectrum identification of proteins. The characteristic polypeptides were obtained through searching Expasy blast database. The m/z of the fragment ions was less than 800. In the paper, the m/z of ion pairs of CYP2C11 were 711.5/232.1, 711.5/319.2, 711.5/466.2 and 711.5/595.3, and the m/z of ESAT-6 (internal standard, IS) were 735.5/215.3, 735.5/389.3, 735.5/460.3 and 735.5/524.3. The relative peak (analyte/IS) area was adopted for the relative quantitative analysis. Compared with the EFV single administration group, the EFV and Tangcao pill combined administration group showed a 1.6-fold increase in CYP2C11. The results of the paper indicated that Tangcao pill may affect drug metabolism by regulating metabolic enzymes such as CYP2C11, but the specific mechanism still unknown.