Effects of detergents on the West Nile virus protease activity.
Detergents such as Triton X-100 are often used in drug discovery research to weed out small molecule promiscuous and non-specific inhibitors which act by aggregation in solution and undesirable precipitation in aqueous assay buffers. We evaluated the effects of commonly used detergents, Triton X-100, Tween-20, Nonidet-40 (NP-40), Brij-35, and CHAPS, on the enzymatic activity of West Nile virus (WNV) protease. Unexpectedly, Triton X-100, Tween-20, and NP-40 showed an enhancement of in vitro WNV protease activity from 2 to 2.5-fold depending on the detergent and its concentration. On the other hand, Brij-35, at 0.001% enhanced the protease activity by 1.5-fold and CHAPS had the least enhancing effect. The kinetic analysis showed that the increase in protease activity by Triton X-100 was dose-dependent. Furthermore, at Triton X-100 and Tween-20 concentrations higher than 0.001%, the inhibition of compound B, one of the lead compounds against WNV protease identified in a high throughput screen (IC(50) value of 5.7+/-2.5 microM), was reversed. However, in the presence of CHAPS, compound B still showed good inhibition of WNV protease. Our results, taken together, indicate that nonionic detergents, Triton X-100, Tween, and NP-40 are unsuitable for the purpose of discrimination of true versus promiscuous inhibitors of WNV protease in high throughput assays.
Department of Microbiology and Immunology, Georgetown University School of Medicine, Washington, DC 20057, United States.
Manolya D
MD
Ezgimen
Niklaus H
NH
Mueller
Tadahisa
T
Teramoto
R
R
Padmanabhan
D003902:Detergents / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D008958:Models, Molecular; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014902:West Nile virus / Q000187:drug effects / Q000201:enzymology*
D003902:Detergents; D011480:Protease Inhibitors; D010447:Peptide Hydrolases