Betaine synthesis in chenopods: localization in chloroplasts
Plants from several families (Chenopodiaceae, Gramineae, Compositae) accumulate betaine (glycine betaine) in response to salt or water stress via the pathway: choline betainal (betaine aldehyde) betaine. Betaine accumulation is probably a metabolic adaptation to stress. Intact protoplasts from leaves of spinach (Spinacia oleracea) oxidized ( UC)choline to betainal and betaine, as did protoplast lysates. Upon differential centrifugation, the ( UC)choline-oxidizing activity of lysates sedimented with chloroplasts. Chloroplasts purified from protoplast lysates by a Percoll cushion procedure retained strong ( UC)choline-oxidizing activity, although the proportion of the intermediate, ( UC)betainal, in the reaction products was usually higher than for protoplasts. Isolated chloroplasts also readily oxidized ( UC)betainal to betaine. Light increased the oxidation of both ( UC)choline and ( UC)betainal by isolated chloroplasts. Similar results were obtained with another chenopod (Beta vulgaris) but not with pea (Pisum sativum), a species that accumulates no betaine. The chloroplast site for betaine synthesis in chenopods contrasts with the mitochondrial site in mammals.
- Research Organization:
- Michigan State Univ., East Lansing, MI (United States)
- DOE Contract Number:
- AC02-76ER01338
- OSTI ID:
- 6085381
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 82:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BETAINE
BIOSYNTHESIS
CARBON 14 COMPOUNDS
OXIDATION
CHOLINE
BIOLOGICAL LOCALIZATION
BIOLOGICAL STRESS
CENTRIFUGATION
CHLOROPLASTS
LEAVES
PLANT CELLS
SPINACH
ALCOHOLS
AMINES
AMINO ACIDS
AMMONIUM COMPOUNDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
DRUGS
FOOD
HYDROXY COMPOUNDS
LABELLED COMPOUNDS
LIPOTROPIC FACTORS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PLANTS
QUATERNARY COMPOUNDS
SEPARATION PROCESSES
SYNTHESIS
VEGETABLES
550301* - Cytology- Tracer Techniques
550201 - Biochemistry- Tracer Techniques