Characterization of the esterase isozymes of Ips typographus (Coleoptera, Scolytidae)

Christian Stauffer, Takahiro Shiotsuki, William Chan, Bruce D. Hammock

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Four esterase isozymes hydrolyzing α-naphthyl acetate (α-NA) were detected screening whole body homogenates of larvae and adults of Ips typographus by electrophoresis. Two of the four isozymes (isozymes 3 and 4) were not detected by α-NA staining in the pupal stage, but topical application of juvenile hormone III (JH III) on the pupa induced these isozymes. The JH esterase (JHE) activity on the gel was associated with the proteins of isozyme 2. The compounds OTFP, PTFP, and DFP inhibited this catalytic activity of isozyme 2 on the gel at low concentrations, whereas the proteins of isozyme 3 and 4 were affected only at higher concentrations. A quantitative developmental study was performed to characterize which of the esterases hydrolyzed JH III, using a putative surrogate substrate for JH (HEXTAT) and α-NA. The I50 of several esterase inhibitors and the JH metabolites were also defined. All findings supported the results that a protein associated with isozyme 2 is catabolizing JH and that isozymes 3 and 4 are the main contributors to the general esterase activity on α-NA. The JHE from Tenebrio molitor was purified by affinity chromatography. Although the recovery was low, an analytical isoelectric focusing gel showed that the JHE activity of the purified enzyme T. molitor cochromatographed at the same pl as the JHE activity of I. typographus.

Original languageEnglish (US)
Pages (from-to)203-221
Number of pages19
JournalArchives of Insect Biochemistry and Physiology
Volume34
Issue number2
StatePublished - 1997

Keywords

  • Developmental profile
  • Ips typographus
  • Juvenile hormone esterase
  • Tenebrio molitor

ASJC Scopus subject areas

  • Insect Science
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physiology
  • Physiology (medical)

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