caa a22 4500 465766072 CHVBK 20180323111914.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF02544327 doi (NATIONALLICENCE)springer-10.1007/BF02544327 Phosphatidylcholine synthesis in the rat: The substrate for methylation and regulation by choline [Elektronische Daten] [Anne Datko, Robert Aksamit, S. Mudd] Two lines of evidence led us to reexamine the possibility that methylation of phosphoethanolamine and its partially methylated derivatives, in addition to methylation of the corresponding phosphatidyl derivatives, plays a role in mammalian phosphatidylcholine biosynthesis: (a) Results obtained by Salerno and Beeler with rat [Salerno, D. M. and Beeler, D. A. (1973)Biochim. Biophys. Acta 326, 325-338] appear to strongly support such a role for methylation of phosphobases; (b) Such reactions have recently been shown to play major roles in phosphatidylcholine synthesis by higher plants [see Datko, A. H. and Mudd, S. H. (1988)Plant Physiol. 88, 854-861 and references therein]. We found that, following coninuous labeling of rat liver with L-[methyl-3H]methionine for 10.4 min (intraperitoneal administration) or for 0.75 min (intraportal administration), virtually no3H was detected in methylated derivatives of phosphoethanolamine, but readily detectable amounts of3H were present in the base moiety of each methylated derivative of phosphatidylethanolamine. Thus, there was no indication that phospho-base methylation makes a significant contribution. Studies of cultured rat hepatoma cells showed definitively for the first time in a mammalian system that choline deprivation up-regulates the rate of flow of methyl groups originating in methionine into phosphatidylethanolamine and derivatives. Even under these conditions, methylation of phosphoethanolamine bases appeared to play a negligible role. American Oil Chemists' Society (AOCS), 1985 Datko Anne Laboratory of General and Comparative Biochemistry, National Institute of Mental Health, Building 36, Room 3D-05, 9000 Rockville Pike, 20892, Bethesda, MD aut Aksamit Robert Laboratory of General and Comparative Biochemistry, National Institute of Mental Health, Building 36, Room 3D-05, 9000 Rockville Pike, 20892, Bethesda, MD aut Mudd S. Laboratory of General and Comparative Biochemistry, National Institute of Mental Health, Building 36, Room 3D-05, 9000 Rockville Pike, 20892, Bethesda, MD aut Lipids Springer-Verlag 25/3(1990-03-01), 135-142 0024-4201 25:3<135 1990 25 11745 https://doi.org/10.1007/BF02544327 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02544327 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Datko Anne Laboratory of General and Comparative Biochemistry, National Institute of Mental Health, Building 36, Room 3D-05, 9000 Rockville Pike, 20892, Bethesda, MD aut NATIONALLICENCE 700 1- Aksamit Robert Laboratory of General and Comparative Biochemistry, National Institute of Mental Health, Building 36, Room 3D-05, 9000 Rockville Pike, 20892, Bethesda, MD aut NATIONALLICENCE 700 1- Mudd S. Laboratory of General and Comparative Biochemistry, National Institute of Mental Health, Building 36, Room 3D-05, 9000 Rockville Pike, 20892, Bethesda, MD aut NATIONALLICENCE 773 0- Lipids Springer-Verlag 25/3(1990-03-01), 135-142 0024-4201 25:3<135 1990 25 11745 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer