文章基本信息

标题：Apolipoprotein B synthesized by Hep G2 cells undergoes fatty acid acylation.
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作者：J M Hoeg ; M S Meng ; R Ronan 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1988
卷号：29
期号：9
页码：1215-1220
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Apolipoprotein B is the principal protein associated with cholesterol transport in the blood and has been proposed to play a central role in human atherogenesis. The unique hydrophobic nature of this large (512 kDa), glycosylated apolipoprotein differs from that of the other apolipoproteins. Since another apolipoprotein, apolipoprotein A-I, has been recently shown to have covalently bound fatty acids, potential fatty acid acylation of apolipoprotein B was investigated. The human hepatoma cell line, Hep G2, synthesizes apoB-100 and secretes the apolipoprotein into the culture medium. After a 24-hr incubation with [14C]palmitate and [14C]stearate, the label was incorporated into apoB-100 when assessed by a sodium dodecyl sulfate polyacrylamide gel electrophoresis, autoradiography, immunoblot analysis, and immunoprecipitation. Hydroxylamine treatment, which hydrolyzes ester and thioester bonds, removed the radiolabel. ApoB-100 isolated from Hep G2 cells by ultracentrifugation and preparative sodium dodecyl sulfate gel electrophoresis was hydrolyzed and analyzed by gas-liquid chromatography-mass spectrometry. In contrast to circulating apoB in low density lipoproteins, both palmitate and stearate were present in newly synthesized apoB-100. These results establish that newly synthesized apoB-100 undergoes covalent acylation with palmitate and stearate. The acylation of apoB may play an important role in lipoprotein particle secretion. In addition, derangements in apoB fatty acid acylation may lead to dyslipoproteinemia.