Comparative metabolism of branched-chain amino acids to precursors of juvenile hormone biogenesis in corpora allata of lepidopterous versus nonlepidopterous insects

Journal Article · Fri Aug 05 04:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:7002675

Brindle, P A; Tsai, L W; Baker, F C

Comparative studies were performed on the role of branched-chain amino acids (BCAA) in juvenile hormone (JH) biosynthesis using several lepidopterous and nonlepidopterous insects. Corpora cardiaca-corpora allata complexes (CC-CA, the corpora allata being the organ of JH biogenesis) were maintained in culture medium containing a uniformly /sup 14/C-labeled BCAA, together with (methyl-/sup 3/H)methionine as mass marker for JH quantification. BCAA catabolism was quantified by directly analyzing the medium for the presence of /sup 14/C-labeled propionate and/or acetate, while JHs were extracted, purified by liquid chromatography, and subjected to double-label liquid scintillation counting. Our results indicate that active BCAA catabolism occurs within the CC-CA of lepidopterans, and this efficiently provides propionyl-CoA (from isoleucine or valine) for the biosynthesis of the ethyl branches of JH I and II. Acetyl-CoA, formed from isoleucine or leucine catabolism, is also utilized by lepidopteran CC-CA for biosynthesizing JH III and the acetate-derived portions of the ethyl-branched JHs. In contrast, CC-CA of nonlepidopterans fail to catabolize BCAA. Consequently, exogenous isoleucine or leucine does not serve as a carbon source for the biosynthesis of JH III by these glands, and no propionyl-CoA is produced for genesis of ethyl-branched JHs. This is the first observation of a tissue-specific metabolic difference which in part explains why these novel homosesquiterpenoids exist in lepidopterans, but not in nonlepidopterans.

• Research Organization: Zoecon Research Institute, Palo Alto, CA (USA)
• OSTI ID: 7002675
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:22; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
ARTHROPODS
BIOLOGICAL FUNCTIONS
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHROMATOGRAPHY
COMPARATIVE EVALUATIONS
COUNTING TECHNIQUES
DOUBLE LABELLING
DRUGS
FUNCTIONS
HORMONES
INSECTS
INVERTEBRATES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LABELLING
LEPIDOPTERA
LEUCINE
LIPOTROPIC FACTORS
LIQUID COLUMN CHROMATOGRAPHY
METHIONINE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PRECURSOR
SCINTILLATION COUNTING
SEPARATION PROCESSES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS