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Endopeptidase activity of larval Lacanobia oleracea corpus allatum: Metabolism of Manduca sexta allatostatin and allatotropin
Author(s) -
Audsley Neil,
Weaver Robert J.
Publication year - 2004
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20027
Subject(s) - manduca sexta , sphingidae , biology , trypsin , corpus allatum , biochemistry , aprotinin , manduca , medicine , endocrinology , enzyme , juvenile hormone , insect , hormone , botany
The degradation of synthetic Manduca sexta allatostatin (Manse‐AS) and allatotropin (Manse‐AT) by enzymes associated with the corpus allatum (CA) of larvae of the tomato moth, Lacanobia oleracea , was investigated using reversed‐phase high performance liquid chromatography and matrix‐assisted laser desorption ionisation‐time of flight mass spectrometry. Manduca sexta allatostatin was metabolised by CA extract to Manse‐AS 5–15 , Manse‐AS 6–15 , and Manse‐AS 7–15 , which indicates enzymic cleavage at the C‐terminal side of arginine residues R 3 and R 5 and the N‐terminal side of R 5 , suggesting this is due to a trypsin‐like enzyme. In support of this, the same degradation products were identified after Manse‐AS was incubated with trypsin, and CA enzymic activity could be inhibited up to 79% by aprotinin. Degradation of Manse‐AT by CA extract was also trypsin‐like, cleaving at the C‐terminal side of the basic residues K 3 and R 11 to produce Manse‐AT 4–13 and Manse‐AT 1–11 . Metabolism by trypsin produced the same deletion peptides, but the major product due to this enzyme was Manse‐AT 4–11 . Hydrolysis of Manse‐AT by CA could only be partially inhibited by high doses of aprotinin (36%), and the CA extract also cleaved Manse‐AT between M 8 and T 9 to produce Manse‐AT 1–8 . A trypsin‐like peptidase appears to be the major enzyme present in the CA of larval L. oleracea that acts to metabolise Manse‐AS and Manse‐AT. In addition, an unidentified enzyme that cleaves between M and T residues degraded Manse‐AT. Arch. Insect Biochem. Physiol. 57:178–189, 2004. British Crown Copyright 2004. Published 2004 Wiley‐Liss, Inc.