Topological Asymmetry of Phospholipids in Membranes

Bergelson, L.D.; Barsukov, L.I.

doi:10.1126/science.327544

Cited by 195 publications

(43 citation statements)

References 74 publications

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“…[42][43][44][45][46]55,56 A signi-cant increase in multiple phosphatidylcholines (PCs) and a decrease in several specic sphingomyelins (SMs) were observed from tumor to adjacent normal tissue particularly, enhanced levels of choline (C 5 in the MALDI-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS), the potassium or sodium adducts form mechanism of which is the same as the result of this study. 46,58 Different formations of these ions produced are contributed to the different main ionization mechanisms of ESI and DAPCI, which are complementary for compounds identi-cation and potential biomarkers discovery.…”

Section: Differentiation Of Tumor From Adjacent Normal Tissue By Multsupporting

confidence: 57%

Differential diagnosis of human lung tumors using surface desorption atmospheric pressure chemical ionization imaging mass spectrometry

et al. 2017

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Section: Differentiation Of Tumor From Adjacent Normal Tissue By Multsupporting

confidence: 57%

Differential diagnosis of human lung tumors using surface desorption atmospheric pressure chemical ionization imaging mass spectrometry

et al. 2017

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“…The second methyltransferase could easily be removed by washing these fractions with 5 mM EDTA, pH 7.0, or by sonication, whereas the first methyltransferase could not be solubilized unless nonionic detergents such as Triton X-100 or Nonidet P-40 were used (unpublished data). These properties might be attributed to their different localization in the membranes and suggest a possible role of these enzymes in the asymmetrical arrangement of phosphatidylethanolamine and phosphatidylcholine in biomembranes (12). Preliminary experiments in our laboratory have shown that both methyltransferases are also present in red blood cell membranes.…”

Section: Requirementmentioning

confidence: 86%

Identification and properties of two methyltransferases in conversion of phosphatidylethanolamine to phosphatidylcholine.

Hirata¹,

Viveros²,

Diliberto³

et al. 1978

Proc. Natl. Acad. Sci. U.S.A.

196

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Two methyltransferases involved in the methylation of phosphatidylethanolamine to form phosphatidytcholine were demonstrated in a microsomal fraction of bovine adrenal medulla. The first methyltransferase catalyzes the methylation of phoshatidylethanol'amine to form phosphatidyl-N-monomethylethanolamine. This enzyme has an optimum pH of 6.5, a low Km for S-adenosyl-L-methionine (1.4 ;M), and an absolute requirement for Mg2+. The second methyltransferase catalyzes the two successive methylations of phosphatidyl-N-monomethylethanolamine to phosphatidyl-N,N-dimethylethanolamine and phosphatidylcholine. In contrast to the first methyltransferase, it has an optimum pH of 10 and a high Km for S-adenosyl-L-methionine (0.1 mM) and does not require MgS+.Several investigations have shown that enzymatic methylations can occur on the amino group of phospholipids to form phosphatidyicholine (1-4). The enzyme(s) catalyzing this sequence of methylation were shown to reside in the microsomes of rat liver and Neurospora. A preparation of rat liver microsomes has been described that catalyzed the stepwise methylation of phosphatidyl-N-monomethylethanolamine to phosphatidylcholine but not of phosphatidylethanolamine (1; 4). The enzyme catalyzing the first methylation step has been suggested to be rate-limiting (1), but its properties have not yet been described. Recently, our laboratory reported on the ability of the enzyme, protein carboxymethylase, to transfer a methyl group from S-adenosyl-L-methionine to carboxy groups of membrane proteins of chromaffin granules in the adrenal medulla (5-7). In studies to examine the effects of cations on this enzyme activity with various membrane fractions, it was observed that methylation of lipids also occurred which depended upon the presence of Mg2+. Since the methylation of phospholipids has not been shown to require Mg2+ (1-4), this led us to search for and characterize the Mg2+ dependent enzyme that methylates lipids. This communication presents evidence that this Mg2+-dependent enzyme is involved in the conversion of phosphatidylethanolamine to phosphatidyl-N-monomethylethanolamine and that a second methyltransferase converts the latter compound to phosphatidylcholine. METHODS AND MATERIALSAssay of Phosphatide Methyltransferases. The methylation of phosphatidylethanolamine to phosphatidyl-N-monomethylethanolamine was assayed by measuring incorporation of the methyl group from S-adenosyl-L-[methyl-3H]methionine into phospholipids. The assay medium, in a 6-ml stoppered polyethylene tube, contained 4 ,uM S-adenosyl-L-[methyl-3H]-The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "'advertisement"9 in accordance with 18 U. S. C. §1734 solely to indicate this fact. 1718 methionine (2 ,uCi), 10 mM MgCl2, 0.1 mM sodium EDTA, 50 mM sodium acetate buffer (pH 6.5), and tissue extract (0.1 mg of protein) in a total volume of 50 1l. The reaction was started by the addition of radioactive S-adenosyl-L...

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“…The concept of an asymmetric distribution of lipids in biological membranes is now well established, and methods employed to assess asymmetry have included the use of specific lipid-hydrolyzing enzymes and chemical reaction with specific group reagents [1,2]. Trinitrobenzene sulphonic acid is a commonly employed reagent for localization of amino groups and has been used to localize amino phospholipids in membranes of erythrocytes [3--7], sarcoplasmic reticulum [8], bacteria [4,7,9--12] and liposomes [13,14].…”

Section: Introductionmentioning

confidence: 99%

A monolayer study of the reaction of trinitrobenzene sulphonic acid with amino phospholipids

Bishop

Bevers

Meer

et al. 1979

Biochimica et Biophysica Acta (BBA) - Biomembranes

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SummaryThe reaction of trinitrobenzene sulphonic acid with amino phospholipids, and in particular phosphatidylethanolamine has been studied by the monolayer technique. Injection of trinitrobenzene sulphonic acid under a monolayer of amino phospholipid results in an increase in surface pressure. The rate and extent of the pressure change is greatly affected by the initial surface pressure, the fatty acid composition of the lipid, and the presence of other non-reactive lipids, especially negatively charged phospholipids.The extent of the reaction was measured with 32P-labelled phospholipids isolated from Bacillus subtilis. Only about 80% of the phosphatidylethanolamine in the monolayer could be converted to its trinitrophenyl derivative. In the presence of negatively charged phospholipids such as cardiolipin or phosphatidylglycerol, a further 20% decrease in the trinitrophenylation of phosphatidylethanolamine was found. The pressure increase occurring during trinitrophenylation could also be correlated with the extent of the reaction by comparison of the force-area curves of pure phosphatidylethanolamine, its trinitrophenyl derivative and mixtures of both compounds.The data may offer an explanation for the observation that incomplete labelling of amino phospholipids frequently occurs in natural membranes and furthermore indicate that the use of chemical labelling techniques in the study of lipid asymmetry in biological membranes must be approached with great caution.

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Topological Asymmetry of Phospholipids in Membranes

Cited by 195 publications

References 74 publications

Differential diagnosis of human lung tumors using surface desorption atmospheric pressure chemical ionization imaging mass spectrometry

Differential diagnosis of human lung tumors using surface desorption atmospheric pressure chemical ionization imaging mass spectrometry

Identification and properties of two methyltransferases in conversion of phosphatidylethanolamine to phosphatidylcholine.

A monolayer study of the reaction of trinitrobenzene sulphonic acid with amino phospholipids

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