title: Comparative kinetics of fatty acid-amino acid conjugate elicitor biosynthesis by midgut tissue microsomes of Lepidopterous caterpillar larvae.
abstract: 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.
authors.affiliation: Center for Chemical Ecology, Department of Entomology, The Pennsylvania State University, Agricultural Sciences & Industries Building, University Park, PA 16802, USA. cglait@gmail.com
authors.forename: Cameron G
authors.initials: CG
authors.lastname: Lait
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Lobaido
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Wiester
authors.forename: Sarah
authors.initials: S
authors.lastname: Kossak
authors.forename: James H
authors.initials: JH
authors.lastname: Tumlinson
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D005227:Fatty Acids / Q000378:metabolism*; D005973:Glutamine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism; D007700:Kinetics; D007814:Larva; D007915:Lepidoptera / Q000378:metabolism*; D008042:Linolenic Acids / Q000096:biosynthesis* / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D005227:Fatty Acids; D008042:Linolenic Acids; C475661:N-linolenoyl-L-glutamine; D005973:Glutamine