Phosphatidylcholine synthesis in castor bean endosperm. I. Metabolism of L-serine. [Ricinus communis]
Endosperm halves from 3-day-old castor bean (Ricinus communis var Hale) were incubated for 30 minutes with L(/sup 14/C)serine, after which label was observed in ethanolamine, choline, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine, ethanolaminephosphate, and CDPethanolamine, but not in cholinephosphate or CDPcholine. Only later did significant amounts of isotope become incorporated into cholinephosphate and CDPcholine. The choline kinase inhibitor hemicholinium-3 prevented the incorporation of label from serine into choline-phosphate and CDPcholine, reduced the incorporation of (/sup 14/C)choline into phosphatidylcholine by 65%, but inhibited the incorporation of label into phosphatidylcholine from serine by only 15%. The inhibitor did not prevent the incorporation of labeled methyl groups from S-adenosyl-L-methionine into phosphatidyldimethylethanolamine plus phosphatidyl-choline. The amount of incorporation of label from the methyl donor was only 8% of that from choline into phosphatidylcholine. The implications of these results for the pathway and regulation of phosphatidylcholine synthesis from the water-soluble precursors are discussed.
- Research Organization:
- Louisiana State Univ., Baton Rouge
- OSTI ID:
- 6020831
- Journal Information:
- Plant Physiol.; (United States), Vol. 84:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHOSPHOLIPIDS
BIOSYNTHESIS
SERINE
METABOLISM
CARBON 14 COMPOUNDS
CASTOR
ENDOSPERM
ENZYME INHIBITORS
PHYSIOLOGY
TRACER TECHNIQUES
AMINO ACIDS
BODY
CARBOXYLIC ACIDS
ESTERS
HYDROXY ACIDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
MEDICINAL PLANTS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PLANT TISSUES
PLANTS
SYNTHESIS
TISSUES
551001* - Physiological Systems- Tracer Techniques