Rapid inactivation of a moth pheromone

Yuko Ishida and
Walter S. Leal*

Maeda–Duffey Laboratory, Department of Entomology, University of California, Davis, CA 95616

Edited by Wendell L. Roelofs, Cornell University, Geneva, NY (received for review June 27, 2005)

Abstract

We have isolated, cloned, and expressed a male antennae-specific pheromone-degrading enzyme (PDE) [Antheraea polyphemus PDE (ApolPDE), formerly known as Sensillar Esterase] from the wild silkmoth, A. polyphemus, which seems essential for the rapid inactivation of pheromone during flight. The onset of enzymatic activity was detected at day 13 of the pupal stage with a peak at day 2 adult stage. De novo sequencing of ApolPDE, isolated from day 2 male antennae by multiple chromatographic steps, led to cDNA cloning. Purified recombinant ApolPDE, expressed by baculovirus, migrated with the same mobility as the native protein on both native polyacrylamide and isoelectric focusing gel electrophoresis. Concentration of ApolPDE (0.5 μM) in the sensillar lymph is ≈20,000 lower than that of a pheromone-binding protein. Native and recombinant ApolPDE showed comparable kinetic parameters, with turnover number similar to that of carboxypeptidase and substrate specificity slightly lower than that of acetylcholinesterase. The rapid inactivation of pheromone, even faster than previously estimated, is kinetically compatible with the temporal resolution required for sustained odorant-mediated flight in moths.

Footnotes

↵ * To whom correspondence should be addressed. E-mail: wsleal{at}ucdavis.edu.
Author contributions: W.S.L. designed research; Y.I. and W.S.L. performed research; Y.I. and W.S.L. analyzed data; and Y.I. and W.S.L. wrote the paper.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: PBPs, pheromone-binding proteins; PDEs, pheromone-degrading enzymes; ApolIE, A. polyphemus integumental esterase; ApolPDE, A. polyphemus PDE enzyme; MS/MS, tandem MS.
Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. AY866480).
Freely available online through the PNAS open access option.