Explorations into the biosynthesis of bioscorine
The biosynthesis of dioscorine in Dioscorea hispida has been studied by the feeding of putative precursors labelled at specific positions with {sup 2}H, {sup 3}H, and {sup 14}C. Administration of (3-{sup 14}C)3-hydroxy-3-methylglutaric acid to D. hispida by the wick method afforded dioscorine labelled preferentially at the C{sub 10} position implying that the biosynthetic pathway to the acetate-derived half of the dioscorine skeleton is going through this compound. Administration of ethyl (6-{sup 14}C)orsellinate to D. hispida by the wick method failed to give an appreciable incorporation into dioscroine thereby disproving an alternative mechanism describing the formation of the acetate-derived half of the dioscorine skeleton. Two attempts to simulate the alternative mechanism by oxidatively cleaving ethyl orsellinate also failed, further disfavoring this mechanism. Administration of (2,3){sup 13}C{sub 2}, {sup 14}C{sub 2}succinic acid, (3-{sup 14}C)aspartic acid and (7a-{sup 14}C)tryptophan by the leaf painting method gave very low incorporations into dioscorine making determination of the source of the nicotinic acid half of the dioscorine skeleton inconclusive. Administration of (6-{sup 2}H, {sup 3}H)nicotinic acid to D. hispida by the wick method afforded dioscorine exhibiting complete retention of {sup 3}H thereby disfavoring a mechanism involving a 3,6-dihydropyridine intermediate in the formation of the dioscorine skeleton.
- Research Organization:
- Minnesota Univ., Minneapolis, MN (USA)
- OSTI ID:
- 5642693
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PROTEINS
BIOSYNTHESIS
ASPARTIC ACID
BIOLOGICAL PATHWAYS
CARBON 13
CARBON 14 COMPOUNDS
DEUTERIUM
GLUTARIC ACID
NICOTINIC ACID
TRACER TECHNIQUES
TRYPTOPHAN
AMINO ACIDS
AROMATICS
AZAARENES
AZINES
AZOLES
CARBON ISOTOPES
CARBOXYLIC ACIDS
DICARBOXYLIC ACIDS
EVEN-ODD NUCLEI
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
INDOLES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
PYRROLES
STABLE ISOTOPES
SYNTHESIS
VITAMIN B GROUP
VITAMINS
550201* - Biochemistry- Tracer Techniques