A sensitive and high-throughput LC-MS/MS method for inhibition assay of seven major cytochrome P450s in human liver microsomes using anin vitrococktail of probe substrates

2014 ◽  
Vol 29 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Li-Ya Liu ◽  
Yong-Long Han ◽  
Jin-Hui Zhu ◽  
Qi Yu ◽  
Quan-Jun Yang ◽  
...  
Keyword(s):  
High Throughput ◽  
Human Liver ◽  
Liver Microsomes ◽  
Cytochrome P450s ◽  
Human Liver Microsomes ◽  
Inhibition Assay

scholarly journals The Potential for CYP2D6 Inhibition Screening Using a Novel Scintillation Proximity Assay-Based Approach

2001 ◽  
Vol 6 (4) ◽  
pp. 225-231 ◽  
Author(s):  
Enock Delaporte ◽  
Donald E. Slaughter ◽  
Marjorie A. Egan ◽  
Gregory J. Gatto ◽  
Albie Santos ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
High Throughput ◽  
Human Liver ◽  
High Performance ◽  
Liver Microsomes ◽  
Inhibitory Effect ◽  
Human Liver Microsomes ◽  
Kinetics Parameters ◽  
Scintillation Proximity Assay ◽  
Demethylase Activity

High throughput inhibition screens for human cytochrome P450s (CYPs) are being used in preclinical drug metabolism to support drug discovery programs. The versatility of scintillation proximity assay (SPA) technology has enabled the development of a homogeneous high throughput assay for cytochrome P450 2D6 (CYP2D6) inhibition screen using [O-methyl-'4C]dextromethorphan as substrate. The basis of the assay was the trapping of the 0- demethylation product, [14C]HCHO, on SPA beads. Enzyme kinetics parameters Vm,,. and apparent Ki,, determined using pooled human liver microsomes and microsomes from baculovirus cells coexpressing human CYP2D6 and NADPH-cytochrome P450 reductase, were 245 pmol [14C]HCHO/min/mg protein and 11,tM, and 27 pmol ['4C]HCHO/min/pmol and 1.6,uM, respectively. In incubations containing either pooled microsomes or recombinant CYP2D6, [14C]dextromethorphan 0-demethylase activity was inhibited in the presence of quinidine (IC50 = 1.0,uM and 20 nM, respectively). By comparison, inhibitors selective for other CYP isoforms were relatively weak (IC50 > 25 tM). In agreement, a selective CYP2D6 inhibitory monoclonal antibody caused greater than 90% inhibition of [14C]dextromethorphan O-demethylase activity in human liver microsomes, whereas CYP2C9/19- and CYP3A4/5-selective antibodies elicited a minimal inhibitory effect. SPA-based [14C]dextromethorphan 0-demethylase activity was also shown to correlate (r2 = 0.6) with dextromethorphan O-demethylase measured by high-performance liquid chromatography in a bank of human liver microsomes (N = 15 different organ donors). In a series of known CYP2D6 inhibitors/substrates, the SPA-based assay resolved potent inhibitors (IC50 <2 μM) from weak inhibitors (IC50 ≥ 20 μM). It is concluded that the SPA-based assay described herein is suitable for CYP2D6 inhibition screening using either native human liver microsomes or cDNA-expressed CYP2D6.

scholarly journals In vitrocharacterization of 4′-(p-toluenesulfonylamide)-4-hydroxychalcone using human liver microsomes and recombinant cytochrome P450s

Xenobiotica ◽  
2015 ◽  
Vol 46 (4) ◽  
pp. 350-356 ◽  
Author(s):  
Boram Lee ◽  
Zhexue Wu ◽  
Taeho Lee ◽  
Xue Fei Tan ◽  
Ki Hun Park ◽  
...  
Keyword(s):  
Human Liver ◽  
Liver Microsomes ◽  
Cytochrome P450s ◽  
Human Liver Microsomes
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