Linoleic acid biosynthesis and characterization of the. Delta. sup 12 desaturase in insects

Thesis/Dissertation · Fri Jan 01 00:00:00 EST 1988

OSTI ID:5160771

Cripps, C

De novo biosynthesis of linoleic acid was demonstrated in vivo in 8 of 32 insect species examined, including both holometabolous and hemimetabolous species. The incorporation of (1-{sup 14}C) acetate into linoleic acid was demonstrated by radio-gas-liquid chromatography (radio-GLC), and in selected species by radio-high-performance liquid chromatography, silver nitrate thin-layer chromatography, radio-GLC and GLC linked to mass spectrometry of ozonolysis products. Analysis of the ozonolysis products clearly demonstrated that the entire molecule was labeled and that synthesis of linoleate was de novo from acetate. The in vivo incorporation of (1-{sup 14}C)acetate into lipid was monitored during the final three stadia of both male and female house crickets, Acheta domesticus. Characterization of the {Delta}{sup 12}-desaturase showed that, in the house cricket, this enzyme is microsomal and requires a reduced pyridine dinucleotide as a cofactor, with NADPH the preferred electron donor. The optimal substrate concentration for desaturation is about 40 uM. Addition of the microsomal supernatant, MgCl{sub 2} or ATP did not enhance activity. The form of the substrate for the desaturase, oleic acid, was determined and appears to be a CoA derivative, as is true for most animal desaturases, rather than a complex lipid, as it is in plants.

• Research Organization: Nevada Univ., Reno, NV (USA)
• OSTI ID: 5160771
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
LINOLEIC ACID
BIOSYNTHESIS
OXYGENASES
CHEMICAL COMPOSITION
ACETATES
CARBON 14 COMPOUNDS
GAS CHROMATOGRAPHY
INSECTS
LIQUID COLUMN CHROMATOGRAPHY
MASS SPECTROSCOPY
NADP
OLEIC ACID
SUBSTRATES
THIN-LAYER CHROMATOGRAPHY
TRACER TECHNIQUES
ANIMALS
ARTHROPODS
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHROMATOGRAPHY
COENZYMES
ENZYMES
INVERTEBRATES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MONOCARBOXYLIC ACIDS
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDOREDUCTASES
SEPARATION PROCESSES
SPECTROSCOPY
SYNTHESIS
550201* - Biochemistry- Tracer Techniques