Development of fluorescent substrates for microsomal epoxide hydrolase and application to inhibition studies

Anal Biochem. 2011 Jul 1;414(1):154-62. doi: 10.1016/j.ab.2011.02.038. Epub 2011 Mar 1.


The microsomal epoxide hydrolase (mEH) plays a significant role in the metabolism of numerous xenobiotics. In addition, it has a potential role in sexual development and bile acid transport, and it is associated with a number of diseases such as emphysema, spontaneous abortion, eclampsia, and several forms of cancer. Toward developing chemical tools to study the biological role of mEH, we designed and synthesized a series of absorbent and fluorescent substrates. The highest activity for both rat and human mEH was obtained with the fluorescent substrate cyano(6-methoxy-naphthalen-2-yl)methyl glycidyl carbonate (11). An in vitro inhibition assay using this substrate ranked a series of known inhibitors similarly to the assay that used radioactive cis-stilbene oxide but with a greater discrimination between inhibitors. These results demonstrate that the new fluorescence-based assay is a useful tool for the discovery of structure-activity relationships among mEH inhibitors. Furthermore, this substrate could also be used for the screening chemical library with high accuracy and with a Z' value of approximately 0.7. This new assay permits a significant decrease in labor and cost and also offers the advantage of a continuous readout. However, it should not be used with crude enzyme preparations due to interfering reactions.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Epoxide Hydrolases / antagonists & inhibitors*
  • Epoxide Hydrolases / metabolism*
  • Fluorescent Dyes / chemistry*
  • Fluorescent Dyes / metabolism*
  • Humans
  • Kinetics
  • Rats
  • Substrate Specificity


  • Enzyme Inhibitors
  • Fluorescent Dyes
  • Epoxide Hydrolases