A detergent-based assay for the detection of promiscuous inhibitors

Nat Protoc. 2006;1(2):550-3. doi: 10.1038/nprot.2006.77.


At micromolar concentrations, many small molecules self-associate into colloidal aggregates that non-specifically inhibit enzymes and other proteins. Here we describe a protocol for identifying aggregate-based inhibitors and distinguishing them from small molecules that inhibit via specific mechanisms. As a convenient proxy for promiscuous, aggregate-based inhibition, we monitor inhibition of beta-lactamase in the absence and presence of detergent. Inhibition that is attenuated in the presence of detergent is characteristic of an aggregate-based mechanism. In the 96-well-format assay described here, about 200 molecules can be tested, in duplicate, per hour for detergent-dependent sensitivity. Furthermore, we also describe simple experiments that can offer additional confirmation of aggregate-based inhibition.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Detergents / chemistry*
  • Detergents / pharmacology
  • Enzyme Inhibitors / analysis*
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Protein Binding / drug effects
  • Protein Denaturation / drug effects
  • beta-Lactamase Inhibitors


  • Detergents
  • Enzyme Inhibitors
  • beta-Lactamase Inhibitors