Development of sensitive esterase assays based on α-cyano-containing esters

Guomin Shan, Bruce D. Hammock

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


A novel approach is reported for the development of fluorogenic esterase reporters using α-cyano-containing esters as substrates. After ester hydrolysis, the released alcohol, a cyanohydrin, rapidly eliminates HCN to yield the corresponding aldehyde resulting in strong fluorescence. The π conjugation of the resulting aldehyde also greatly enhances UV absorption and red shifts fluorescence emission relative to a corresponding alcohol or phenol. Two substrates, R/S-acetic acid cyano-(6-methoxynaphthalen-2-yl)-methyl ester (compound I) and trans/cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid R/S-cyano-(6-methoxynaphthalen-2-yl)-methyl ester (compound II), were synthesized and evaluated as substrates. Such α-cyano substrates possess very low background fluorescence and are more stable under enzyme assay conditions than phenolic substrates due to the aliphatic cyano group. The higher molar absorbtivity and quantum yield of the aldehyde, along with its larger Stokes' shift combined with the increased stability and lower background signal of the cyanohydrin substrate, increases the utility and sensitivity of the resulting assays over current methods. Moreover, compound II showed high selectivity to pyrethroid-cleaving esterases and may provide a direct tool to monitor pyrethroid resistance in insects.

Original languageEnglish (US)
Pages (from-to)54-62
Number of pages9
JournalAnalytical Biochemistry
Issue number1
StatePublished - Dec 1 2001


  • α-cyanoesters
  • Enzyme reporter
  • Esterase
  • Fluorogenic substrate

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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