Abstract
Endosperm halves from 3-day-old castor bean (Ricinus communis var Hale) were incubated for 30 minutes with l-[14C]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 cholinephosphate and CDPcholine, reduced the incorporation of [14C]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 phosphatidylcholine. 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.
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- BLIGH E. G., DYER W. J. A rapid method of total lipid extraction and purification. Can J Biochem Physiol. 1959 Aug;37(8):911–917. doi: 10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
- Bieleski R. L. Turnover of Phospholipids in Normal and Phosphorus-deficient Spirodela. Plant Physiol. 1972 May;49(5):740–745. doi: 10.1104/pp.49.5.740. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bygrave F. L., Dawson R. M. Phosphatidylcholine biosynthesis and choline transport in the anaerobic protozoon Entodinium caudatum. Biochem J. 1976 Dec 15;160(3):481–490. doi: 10.1042/bj1600481. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DELWICHE C. C., BREGOFF H. M. Pathway of betaine and choline synthesis in Beta vulgaris. J Biol Chem. 1958 Aug;233(2):430–433. [PubMed] [Google Scholar]
- Hanson A. D., Rhodes D. C Tracer Evidence for Synthesis of Choline and Betaine via Phosphoryl Base Intermediates in Salinized Sugarbeet Leaves. Plant Physiol. 1983 Mar;71(3):692–700. doi: 10.1104/pp.71.3.692. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore T. S. Phosphatidylcholine synthesis in castor bean endosperm. Plant Physiol. 1976 Mar;57(3):382–386. doi: 10.1104/pp.57.3.382. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore T. S. Phospholipid turnover in soybean tissue cultures. Plant Physiol. 1977 Nov;60(5):754–758. doi: 10.1104/pp.60.5.754. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Singh H., Privett O. S. Incorporation of 33P in soybean phosphatides. Biochim Biophys Acta. 1970 Feb 10;202(1):200–202. doi: 10.1016/0005-2760(70)90236-5. [DOI] [PubMed] [Google Scholar]
- Voelker D. R. Phosphatidylserine functions as the major precursor of phosphatidylethanolamine in cultured BHK-21 cells. Proc Natl Acad Sci U S A. 1984 May;81(9):2669–2673. doi: 10.1073/pnas.81.9.2669. [DOI] [PMC free article] [PubMed] [Google Scholar]