Some properties of phosphatidylcholine exchange protein purified from beef liver

Kamp, H.H.; Wirtz, K.W.A.; Deenen, L.L.M. Van

doi:10.1016/0005-2736(73)90196-x

Cited by 249 publications

(76 citation statements)

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“…Antibodies against the phospholipid exchange proteins were induced in rabbits as described previously [14]. Three weeks after a inoculation with 0.3 mg of protein the rabbit was bled and the immunoglobulin fraction isolated from the serum by precipital ion with ammonium sulfate at 45 % of saturation.…”

Section: Immunological Studiesmentioning

confidence: 99%

Some Properties of Phospholipid Exchange Proteins from Rat Liver

Lumb

Kloosterman

Wirtz

et al. 1976

European Journal of Biochemistry

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The phospholipid exchange proteins of rat liver that catalyze the transfer of phosphatidylcholine and phosphatidylinositol from rat liver microsomes to liposomes, have been purified and characterized.Two proteins were detected with dual specificities catalyzing the transfer of both phosphatidylinositol and phosphatidylcholine. Both proteins showed a strong preference for phosphatidylinositol transferring 8 to 9 times as much of the microsomal phosphatidylinositol pool as the microsomal phosphatidylcholine pool. The two proteins had iso-electric points of 5.1 and 5.3 and were purified 300-fold and 500-fold, respectively.A protein that catalyzed specifically the transfer of phosphatidylcholine, was purified 7000-fold. This protein had an iso-electric point of 8.4 and a molecular weight of approximately 16 000 calculated from Sephadex G-50 chromatography and sodium dodecylsulfate-polyacrylamide gel electrophoresis ; the amino acid composition was determined. An antiserum against this protein was raised in rabbits. Treatment of a rat liver supernatant fraction with the antiserum immunoglobulin fraction demonstrated that 60 % of the phosphatidylcholine transfer activity is due to this protein.The transfer of phospholipids between membranes has been shown to be stimulated by proteins in the 105000xg supernatant of a variety of cells [1,2]. It has been suggested that these proteins play a role in determining the phospholipid composition of eucaryotic cell membranes [3], in membrane biogenesis [2] and possibly in synaptic transmission of nerve impulses [4]. Phospholipid exchange proteins may thus be important to many membrane-associated functions.The transfer of phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine between membranes has been demonstrated with rat liver [5 -101 and bovine liver supernatant [l 11. Recent studies have indicated that bovine brain and liver supernatant contain one exchange protein specific for phosphatidylcholine, and two exchange proteins both of which transfer phosphatidylinositol and, to a lesser extent, phosphatidylcholine [12]. All three proteins are acidic with iso-electric points between 5 and 6. In the present study we have further characterized the phosphatidylinositol and phosphatidylcholine exchange proteins in rat liver.Here we report the presence of an exchange protein in rat liver with an iso-electric point of 8.4 that transfers specifically phosphatidylcholine. In addition two proteins have been partially characterized with isoelectric points of 5.1 and 5.3 and transfer activities towards both phosphatidylinositol and phosphatidylcholine. While this work was in progress a report appeared showing phosphatidylcholine transfer activity in rat intestinal supernatant [13]. On iso-electric focusing this activity concentrated at both acidic (4.5-5.3) and basic (8-9) iso-electric points. MATERIALS AND METHODS Purgication of Phosphatidylinositol and Phosphatidylcholine Exchange ProteinsLivers were obtained from Wistar rats and stored at -20 "C until used. Prior to use ...

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Section: Immunological Studiesmentioning

confidence: 99%

Some Properties of Phospholipid Exchange Proteins from Rat Liver

Lumb

Kloosterman

Wirtz

et al. 1976

European Journal of Biochemistry

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“…Extraction of bovine liver PC-TP by organic solvents showed that one PC-TP molecule contains one molecule of non-covalently bound PC [2,7]. These data indicate that PC-TP has a binding cavity for PC.…”

Section: Introductionmentioning

confidence: 81%

“…Upon purification, the protein contains PC in a molar ratio of 1 : 1 [2]. So far, the preference of PC-TP for certain PC species has been determined using in vitro binding and transfer activity assays.…”

Section: Discussionmentioning

confidence: 99%

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Phosphatidylcholine transfer protein from bovine liver contains highly unsaturated phosphatidylcholine species

et al. 1996

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“…Lipids were extracted from brush border membrane vesicles according to [5]. Phosphatidylcholine exchange protein was prepared from beef liver as in [6] except that the last purification step by gel filtration on Sephadex G-50 was omitted. The exchange protein was purified 710-fold.…”

Section: Introductionmentioning

confidence: 99%