The Enzymatic Formation of Lecithin from Cytidine
نویسندگان
چکیده
The enzyme preparations used in this study consisted of particulate fractions from frozen chicken liver or fresh rat liver isolated from 0.25 M sucrose homogenates by a method already described (1). These preparations contained both mitochondria and microsomes. The enzyme was suspended in 0.02 M Tris buffer of pH 8.0 containing 0.001 M Versene in a concentration of 20 to 40 mg. per ml. and could be stored in the deep freeze for several weeks without loss of activity. Occasional preparations could be greatly increased in activity by thorough dialysis against the TrisVersene buffer. This effect is probably due to the removal of calcium ions, which are extremely inhibitory to the enzyme. D-1,QDiglyceride was obtained from egg lecithin by the action of the lecithinase D of Clostridium perfr%gens toxin (5) which was the gift
منابع مشابه
The enzymatic synthesis of inositol monophosphatide.
The enzymatic synthesis of inositol monophosphatide has been described in reports by Agranoff et al. (l), Thompson et al. (2), and Paulus and Kennedy (3, 4). An enzymatic reaction in which free inositol is incorporated into inositol phosphatide, stimulated by the addition of any of a number of cytidine nucleotides, including cytidine 5’-monophosphate and cytidine diphosphate choline, was fnst o...
متن کاملThe enzymatic synthesis of sphingomyelin.
The role of cytidine coenzymes in phospholipide biosynthesis is now well established (1, 2). Since sphingomyelin has a phosphorylcholine (PC) moiety similar to that found in lecithin, it ha.s been proposed (3) that it is synthesized enzymatically in a reaction in which the phosphorylcholine moiety of CDPcholine is transferred to the free primary hydroxyl group of a ceramide (N-acylsphingosine) ...
متن کاملIn vivo studies on pathways for the biosynthesis of lecithin in the rat.
The in vivo biosynthesis of lecithin in rats has been studied with the precursors choline-1,2-(14)C, ethanolamine-1,2-(14)C and methionine-CH(3)-(14)C or -CH(3)-(3)H. Lecithin synthesis from choline is rapid in all organs. No sex difference was observed in this pathway. The biosynthesis of lecithin by methylation of phosphatidyl ethanolamine is of quantitative significance in the liver, but not...
متن کاملThe enzymatic formation of sphingomyelin from ceramide and lecithin in mouse liver.
The conversion of W-labeled fatty acylsphingosine and phosphatidyl[14C]choline to sphingomyelin could be demonstrated in lyophilized microsomes from mouse liver. Radioactive CDP-choline did not act as a choline donor. No cofactors were needed, although CDP-choline and P-choline exerted some stimulatory action. The unnatural ceramide, acetyl threo-sphingosine, could be converted to the correspon...
متن کاملPhospholipid Variations in Mutant Strains of Neurospora Crassa.
The present studies were undertaken to determine the extent to which the phospholipid composition of Neurosporn crama can be altered by mutations studied in conjunction with controlled supplementation. Previous work in this laboratory has shown that a mutation involving an enzyme concerned with lecithin synthesis can result in a lecithin-deficient strain (1, 2). The methylation of phosphatidyle...
متن کامل