Distinctive structural and kinetic properties of an unusual juvenile hormone-hydrolyzing esterase Academic Article uri icon

Overview

MeSH Major

  • Carboxylic Ester Hydrolases
  • Insect Proteins
  • Juvenile Hormones

abstract

  • The insect juvenile hormone specific esterases (JHEs), related to acetylcholinesterases but exhibiting substrate specificity for juvenile hormone (JH), are essential enzymes for normal insect development, making them attractive targets for biorationally designed, environmentally safe pesticides. We examine here a new enzyme, JHER, related to, but yet structurally, biochemically, and kinetically distinct from, the classical JHE. Both classical JHE and baculovirus-expressed JHER hydrolyze JH show disproportionately higher catalytic rates at higher substrate concentrations (in contrast to substrate inhibition reported for acetylcholinesterase) and are similarly inhibited by an organophosphate. However, JHER, which possesses an unusual cysteine residue at +1 to the catalytic serine, is less sensitive to trifluoromethyl ketone transition state analogs designed around the structure of JH. We propose a model in which JHER is expressed just prior to metamorphosis for hydrolysis of a JH-like substrate with hydrophobic backbone, a proximal ester, and a terminal expoxide or related substitution.

publication date

  • May 27, 2000

Research

keywords

  • Academic Article

Identity

Language

  • eng

Digital Object Identifier (DOI)

  • 10.1006/bbrc.2000.2711

PubMed ID

  • 10872796

Additional Document Info

start page

  • 12

end page

  • 7

volume

  • 272

number

  • 1