Processing and transport of human small intestinal lactase‐phlorizin hydrolase (LPH)

FEBS Letters

Y. Naim, Hassan¹ 

[1] Protein Secretion Group, Institute of Microbiology, Heinrich-Heine-University of Düsseldorf, Universitätsstr. 1, Gebäude 26.12, D-40225 Düsseldorf, Germany

关键词: Lactase-phlorizin hydrolase;    Human;    intestine;    Carbohydrate processing;    Intracellular transport;    LPH;    lactase-phlorizin hydrolase (EC 3.2.1.23-62);    pro-LPH;    pro-lactase-phlorizin hydrolase;    LPHm;    mature brush border lac-tase-phlorizin hydrolase (160 kDa);    dNM;    deoxynojirimycin;    dMM;    deoxymannojirimycin;    pro-LPH dNMand LPH dNM;    pro-LPH and LPH obtained in the presence of dNM;    pro-LPH dMMand LPH dMMpro-LPH and LPH obtained in the presence of dMM;    pro-LPH Swa and LPHs Swapro-LPH and LPH obtained in the presence of swainsonine;    endo F/GF;    endo-β-N-acetylglucosaminidase F/glycopeptidase F;    endo H;    endo-β-N-acetylgrucosaminidase H;    IM;    intracellular membranes;    BBM;    brush border membranes;    SDS-PAGE;    sodium-dodecyi sulfate-polyacrylamide gel electrophoresis;   

DOI  :  10.1016/0014-5793(94)80521-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effect of glycosylation on the intracellular transport of human intestinal lactase-phlorizin hydrolase (LPH) was investigated by biosynthetic labeling of biopsy samples in the presence or absence of glycosidase inhibitors. In the presence of deoxynojirimycin (dNM) and deoxymannojirimycin (dMM), endo H sensitive LPH glycoforms of M _r = 135,000 in both cases were produced (LPH _dNM and LPH _dMM ). The LPH glycoform generated in the presence of swainsonine had an apparent molecular mass of 141,000 (LPH _Swa ) and was partially sensitive to endo H. By contrast to unmodified mature LPH (LPH_m M _r = 160,000), these glycoforms are either not O-glycosylated (LPH _dNM and LPH _dMM ) or partially O-glycosylated (LPH _Swa ) indicating that processing of N-linked carbohydrates has direct effects on the O-glycosylation of pro-LPH. Analysis of transport kinetics of the various glycoforms strongly suggested that carbohydrate modification does not affect the transport of pro-LPH from the cis-Golgi to the cell surface, but could be rate limiting at the level of the ER.

【 授权许可】

Unknown