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 Km values for coupling of sodium linolenate were 8.75±0.79, 14.3±3.7 and 20.7±3.4 mM and Vmax 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 Km values for coupling of L-glutamine were 10.5±0.26, 22.3±2.0 and 18.9±2.4 mM and Vmax 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.
All Science Journal Classification (ASJC) codes
- Insect Science