Exposure to galactose oxidase of GM1 ganglioside molecular species embedded into phospholipid vesicles

FEBS Letters

Palestini, Paola¹  Masserini, Massimo¹  Tettamanti, Guido¹ 

[1] Department of Medical Chemistry and Biochemistry, University of Milan, Milan, Italy

关键词: Galactose oxidase;    Ganglioside;    Artificial membrane;    GAO;    Galactose oxidase (EC 1.1.3.9);    DPPC;    dipalmitoylphosphatidylcholine;    EPC;    egg phosphatidylcholine;    LUVs;    large unilamellar vesicles;    LCB;    long-chain base;    HPLC;    high performance liquid chromatography;    HPTLC;    high-performance thin-layer chromatography;    GM1-ox;    oxidized GM1;    NeuAc;    N-acetylneuraminic acid. Ganglioside nomenclature follows Svennerholm [1] and the IUPAC-IUB recommendations [2];   

DOI  :  10.1016/0014-5793(94)00765-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The exposure of GM1 molecular species present in the native ganglioside, carrying C18:1 or C20:1 long-chain bases (LCB), to Dactylium dendroides galactose oxidase was studied. When native GM1 (49.3% C18:1 and 50.7% C20:1 LCB, respectively), was inserted in dipalmitoylphosphatidylcholine vesicles and partially oxidized (10%), the proportion of C18:1 and C20:1 species in the oxidized GM1 was 59.6% and 40.4%, respectively, suggesting a preferential action of the enzyme on the shorter species. The V _max of the enzyme was higher on C18:1 GM1 than on C20:1 GM1. The molecular species were affected without any preference after partial (10%) oxidation of GM1 incorporated in egg phosphatidylcholine vesicles or in micellar form. These data indicate that the exposure of the terminal galactose moiety of GM1 ganglioside to galactose oxidase is affected by the ganglioside ceramide composition as well as the phospholipid environment, that presumably determine the distribution (molecular dispersion, segregation) of the ganglioside within the membrane.

【 授权许可】

Unknown