Fatty acid synthesis in endosperm of young castor bean seedlings. [/sup 14/C tracer technique]
Enzyme assays on organelles isolated from the endosperm of germinating castor bean (Ricinus communis) by sucrose density gradient centrifugation showed that fatty acid synthesis from (/sup 14/C)malonyl-CoA was localized exclusively in the plastids. The optimum pH was 7.7 and the products were mainly free palmitic and oleic acids. Both NADH and NADPH were required as reductants for maximum activity. Acetyl-CoA, and acyl-carrier protein from Escherichia coli increased the rate of fatty acid synthesis, while low O/sub 2/ levels suppressed synthesis. In the absence of NADPH or at low O/sub 2/ concentration, stearic acid became a major product at the expense of oleic acid. Fatty acid synthesis activity was highest during the first 3 days of germination, preceding the maximum development of mitochondria and glyoxysomes. It is proposed that the plastids are the source of fatty acids incorporated into the membranes of developing organelles.
- Research Organization:
- Univ. of California, Santa Cruz
- OSTI ID:
- 6632014
- Journal Information:
- Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 62; ISSN PLPHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BIOASSAY
BIOCHEMISTRY
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CASTOR
CELL CONSTITUENTS
CENTRIFUGATION
CHEMISTRY
COENZYMES
ENDOSPERM
ENZYMES
GERMINATION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MEDICINAL PLANTS
MITOCHONDRIA
NADP
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PH VALUE
PLANT TISSUES
PLANTS
SEEDLINGS
SEPARATION PROCESSES
SYNTHESIS
TRACER TECHNIQUES