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Comparative kinetics of fatty acid–amino acid conjugate elicitor biosynthesis by midgut tissue microsomes of Lepidopterous caterpillar larvae
Author(s) -
Lait Cameron G.,
Lobaido Melanie J.,
Wiester Amy J.,
Kossak Sarah,
Tumlinson James H.
Publication year - 2010
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.20392
Subject(s) - manduca sexta , biology , biosynthesis , biochemistry , glutamine , sphingidae , helicoverpa zea , linolenic acid , fatty acid , amino acid , enzyme , linoleic acid , botany , insect , larva , noctuidae
N ‐Linolenoyl‐ L ‐glutamine is one of several structurally similar fatty acid–amino acid conjugate (FAC) elicitors found in the oral secretions of Lepidopterous caterpillars and its biosynthesis is catalyzed by membrane‐associated alimentary tissue enzyme(s). FAC elicitors comprise 17‐hydroxylated or non‐hydroxylated linolenic acid coupled with L ‐glutamine or L ‐glutamate by an amide bond. We demonstrate in vitro biosynthesis of N ‐linolenoyl‐ L ‐glutamine by Manduca sexta , Heliothis virescens, and Helicoverpa zea tissue microsomes. Comparison of N ‐linolenoyl‐ L ‐glutamine biosynthesis kinetics for these species suggests that concurrent biosynthesis and hydrolysis contribute to proportions of FAC elicitors found in their oral secretions. The apparent K m values for coupling of sodium linolenate were 8.75±0.79, 14.3±3.7 and 20.7±3.4 mM and V max values were 2.92±0.14, 6.81±1.2 and 4.95±0.55 nmol/min/mg protein for H. zea , H. virescens and M. sexta , respectively. The K m values for coupling of L ‐glutamine were 10.5±0.26, 22.3±2.0 and 18.9±2.4 mM and V max values were 1.78±0.21, 3.71±0.50 and 2.49±0.41 nmol/min/mg of protein for H. zea , H. virescens and M. sexta , respectively. © 2010 Wiley Periodicals, Inc.