Incorporation of oxygen into abscisic acid and phaseic acid for molecular oxygen
Abscisic acid accumulates in detached, wilted leaves of Xanthium strumariu. When these leaves are subsequently rehydrated, phaseic acid, a catabolite of abscisic acid, accumulates. Analysis by gas chromatography-mass spectrometry of phaseic acid isolated from stressed and subsequently rehydrated leaves placed in an atmosphere containing 20% /sup 18/O/sub 2/ and 80% N/sub 2/ indicates that one atom of /sup 18/O is incorporated in the 6'-hydroxymethyl group of phaseic acid. This suggests that the enzyme that converts abscisic acid to phaseic acid is an oxygenase. Analysis by gas chromatography-mass spectrometry of abscisic acid isolated from stressed leaves kept in an atmosphere containing /sup 18/O/sub 2/ indicates that one atom of /sup 18/O is presented in the carboxyl group of abscisic acid. Thus, when abscisic acid accumulates in water-streesed leaves, only one of the four oxygens present in the abscisic acid molecule is derived from molecular oxygen. This suggest that either (a) the oxygen present in the 1'-, 4'-, and one of the two oxygens at the 1-position of abscisic acid arise from water, or (b) there exists a stored precursor with oxygen atoms already present in the 1'- and 4'-positions of abscisic acid which is converted to abscisic acid under conditions of water stress. 17 references, 2 figures, 1 tables.
- Research Organization:
- Michigan State Univ., East Lansing, MI (United States)
- DOE Contract Number:
- AC02-76ER01338
- OSTI ID:
- 5932422
- Journal Information:
- Plant Physiol.; (United States), Vol. 75:1
- Country of Publication:
- United States
- Language:
- English
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ORGANIC ACIDS
BIOCHEMISTRY
BIOLOGICAL ACCUMULATION
BIOLOGICAL STRESS
CHEMICAL ANALYSIS
ENZYME ACTIVITY
GAS CHROMATOGRAPHY
HERBS
LEAVES
MASS SPECTROSCOPY
OXYGEN 18
OXYGENASES
WATER
CHEMISTRY
CHROMATOGRAPHY
ENZYMES
EVEN-EVEN NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
NUCLEI
ORGANIC COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PLANTS
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
550201* - Biochemistry- Tracer Techniques