title: On-line screening of matrix metalloproteinase inhibitors by capillary electrophoresis coupled to ESI mass spectrometry.
abstract: Capillary electrophoresis (CE) with the use of mass spectrometry (MS) has been considered as a unique tool for microscale enzyme assay and inhibitor screening. In this study, matrix metalloproteinase-9 (MMP-9) was selected as target enzyme due to its important role in tumor invasion and metastasis. In order to define the optimal MS parameters, a two level half fraction factorial experimental design was performed. A background electrolyte consisting of 20mM ammonium acetate (pH 6.8) and a sheath liquid of water-methanol (50:50, v/v) containing 0.05% formic acid at a flow rate of 4μl/min were selected. This system was operated in the positive ion mode with a detection-limit of 10nM for the MMP reaction product and provided 60 folds enhancement of sensitivity by using selected reaction monitoring detection compared with MS full scan mode, which significantly increased the detectability of the system and therefore reduced the enzyme reaction time in both off-line and in-line mode. Both electrophoretically mediated microanalysis and pressure mediated microanalysis combined with MS detection were investigated for MMP inhibitor screening. Good repeatability (RSD of peak area and migration time were lower than 5.0%) and linearity (R(2)>0.996) were obtained for both in-capillary approaches. Several tetracycline antibiotics and natural products were selected to test the system. The results indicated an agreement on the ranking of inhibitory potency for both in-capillary approaches.
authors.affiliation: Laboratory for Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, KU Leuven, Herestraat 49, PB 923, B-3000 Leuven, Belgium.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Dou
authors.forename: Yaozuo
authors.initials: Y
authors.lastname: Yuan
authors.forename: Shuli
authors.initials: S
authors.lastname: Man
authors.forename: Kris
authors.initials: K
authors.lastname: Wolfs
authors.forename: Erwin
authors.initials: E
authors.lastname: Adams
authors.forename: Ann
authors.initials: A
authors.lastname: Van Schepdael
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D016014:Linear Models; D020780:Matrix Metalloproteinase 9 / Q000737:chemistry / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors / Q000032:analysis* / Q000494:pharmacology*; D000432:Methanol; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013754:Tetracyclines / Q000032:analysis / Q000494:pharmacology
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D013754:Tetracyclines; D020780:Matrix Metalloproteinase 9; D000432:Methanol