Gulonolactone oxidase activity‐dependent intravesicular glutathione oxidation in rat liver microsomes

FEBS Letters

Benedetti, Angelo¹  Braun, László²  Marcolongo, Paola¹  Kardon, Tamás²  Puskás, Ferenc²  Csala, Miklós²  Bánhegyi, Gábor²  Mandl, József² 

[1] Istituto di Patologia Generale, Università di Siena, Siena, Italy;Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University of Medicine, P.O.B. 260, H-1444 Budapest, Hungary

关键词: Gulonolactone oxidase;    Ascorbate;    Glutathione;    Endoplasmic reticulum;    GSH;    glutathione (reduced form);    GSSG;    glutathione (oxidised form);    PEG;    polyethylene glycol;    MOPS;    4-morpholinepropanesulfonic acid;    DIDS;    4;    4′-diisothiocyanostilbene-2;    2′-disulfonic acid;   

DOI  :  10.1016/S0014-5793(98)00678-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The orientation of gulonolactone oxidase activity was investigated in rat liver microsomes. Ascorbate formation upon gulonolactone addition resulted in higher intravesicular than extravesicular ascorbate concentrations in native microsomal vesicles. The intraluminal ascorbate accumulation could be prevented or the accumulated ascorbate could be released by permeabilising the vesicles with the pore-forming alamethicin. The formation of the other product of the enzyme, hydrogen peroxide caused the preferential oxidation of intraluminal glutathione in glutathione-loaded microsomes. In conclusion, these results suggest that the orientation of the active site of gulonolactone oxidase is intraluminal and/or the enzyme releases its products towards the lumen of the endoplasmic reticulum.

【 授权许可】

Unknown