With the advance of drug development and research techniques, the drug metabolic processes and mechanism can be more deeply achieved. As the drug metabolism and pharmacokinetics process are mediated by drug metabolizing enzymes and transporters, study of drug metabolizing enzymes and transporters has become an important part for drug development. The traditional immunoassays with low sensitivity and poor specificity can not reflect the accurate expression level of drug metabolizing enzymes and transporters. We now give a brief review on the quantitative study of drug metabolizing enzymes and transporters by mass spectrometry-based proteomic approach.

The human serum proteome is closely associated with the state of the body. Endogenous peptides derived from proteolytic enzymes cleaving on serum proteins are widely studied due to their potential application in disease-specific marker discovery. However, the reproducibility of peptidome analysis of endogenous peptides is significantly influenced by the proteolytic enzymes within body fluids, thereby limiting the clinical use of the endogenous peptides. We comprehensively investigated the N and C terminus of endogenous peptides using peptidomics. The cleavage site patterns of the N and C terminus and adjacent sites from all the identified endogenous peptides were highly conserved under different sample preparation conditions, including long-term incubation at 37°C and pretreatment with repeated freeze-thaw cycles. Furthermore, a distinguishable cleavage site pattern was obtained when a different disease serum was analyzed. The conserved cleavage site pattern derived from proteolytic enzymes holds potential in highly specific disease diagnosis.
Carcinoma, Hepatocellular ; blood ; diagnosis ; Chromatography, High Pressure Liquid ; Chromatography, Reverse-Phase ; Humans ; Liver Neoplasms ; blood ; diagnosis ; Mass Spectrometry ; Nanotechnology ; Peptide Hydrolases ; metabolism ; Peptides ; blood ; Protein Structure, Tertiary ; Proteome ; analysis ; Proteomics ; Silicon Dioxide ; chemistry ; Time Factors

Objective : To investigate the expression , synergistic relationship and clinical significance of alcohol dehydrogenase (ADH1A) and vascular endothelial growth factor-A (VEGFA) in hepatocellular carcinoma (HCC) . Methods : The expression and correlation of ADH1A and VEGFA in HCC and adjacent normal tissues were ana lyzed by GEPIA . TCGA and GSEA were used to analyze the pathway of ADH1A in HCC . The clinical and patho logical data of 84 patients with HCC were collected , and 54 patients with paracancer normal tissue samples were se lected as controls to analyze the correlation between ADH1A and VEGFA and clinicopathological parameters of HCC . Immunohistochemistry was used to detect the protein expression of ADH1A and VEGFA in cases and con trols , and the correlation between the expression of ADH1A and VEGFA and the clinical progression and prognosis of patients with HCC was analyzed based on clinical pathological parameters and Kaplan Meier. Results : Bioinfor matics analysis found that ADH1A was low expressed in HCC and VEGFA was highly expressed in HCC , and there was a negative correlation between the two ( P < 0.001) ; immunohistochemical detection results showed that the expression of ADH1A in HCC tissue was lower than that in normal tissue adjacent to cancer (P < 0.01) while the expression rate of VEGFA in HCC tissue was significantly higher than that of normal tissue adjacent to cancer (P < 0.01) ; The recurrence rate of vascular thrombus and HCC patients in HCC group with high expression of ADH1A was lower (P < 0.05) . The proportion of tumor diameter > 5 cm , high TNM stage , microsatellite and G2 G3 dif ferentiation in HCC tissues in VEGFA high expression group was higher (P < 0.05) . Kaplan Meier survival analy sis showed that patients with high ADH1A expression and low VEGFA expression had a higher five year survival rate . Conclusion Low expression of ADH1A and high expression of VEGFA in tumor tissues of patients with HCC indicate tumor progression and can be used as one of the prognostic evaluation indicators for patients with HCC .