Evaluation of α-cyanoesters as fluorescent substrates for examining interindividual variation in general and pyrethroid-selective esterases in human liver microsomes

Craig E. Wheelock, Åsa M. Wheelock, Rong Zhang, Jeanette E. Stok, Christophe Morisseau, Susanna E. Le Valley, Carol E. Green, Bruce D. Hammock

Research output: Contribution to journalArticle

48 Scopus citations


Carboxylesterases hydrolyze many pharmaceuticals and agrochemicals and have broad substrate selectivity, requiring a suite of substrates to measure hydrolytic profiles. To develop new esterase substrates, a series of α-cyanoesters that yield fluorescent products upon hydrolysis was evaluated for use in carboxylesterase assays. The use of these substrates as surrogates for Type II pyrethroid hydrolysis was tested. The results suggest that these novel analogs are appropriate for the development of high-throughput assays for pyrethroid hydrolase activity. A set of human liver microsomes was then used to determine the ability of these substrates to report esterase activity across a small population. Results were compared against standard esterase substrates. A number of the esterase substrates showed correlations, demonstrating the broad substrate selectivity of these enzymes. However, for several of the substrates, no correlations in hydrolysis rates were observed, suggesting that multiple carboxylesterase isozymes are responsible for the array of substrate hydrolytic activity. These new substrates were then compared against α-naphthyl acetate and 4-methylumbelliferyl acetate for their ability to detect hydrolytic activity in both one- and two-dimensional native electrophoresis gels. Cyano-2-naphthylmethyl butanoate was found to visualize more activity than either commercial substrate. These applications demonstrate the utility of these new substrates as both general and pyrethroid-selective reporters of esterase activity.

Original languageEnglish (US)
Pages (from-to)208-222
Number of pages15
JournalAnalytical Biochemistry
Issue number2
StatePublished - Apr 15 2003



  • Cytochrome P450
  • Esterase
  • Fluorescent substrate
  • High-throughput assay
  • Human liver microsomes
  • Native 2D gel electrophoresis
  • Pyrethroid

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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