Quintart J, Baudhuin P, Courtoy P J
Laboratoire de Chimie Physiologique, University of Louvain, Brussels.
Eur J Biochem. 1989 Oct 1;184(3):567-74. doi: 10.1111/j.1432-1033.1989.tb15051.x.
In order to label the vesicles involved in transcellular transfer (transcytosis) through hepatocytes, polymeric IgA (pIgA) was conjugated to horseradish peroxidase (HRP) and injected into rats. The endosomes containing this ligand at 10 or 20 min after injection were isolated by the diaminobenzidine-induced density-shift procedure and their content in various marker enzymes was measured. The endosomes carrying pIgA-HRP 10 min after injection contained only traces of 5'-nucleotidase and low amounts of alkaline phosphodiesterase I. The estimated marker enzyme content is similar to that observed for the particles containing galactosylated bovine serum albumin conjugated to HRP, a ligand degraded in lysosomes. However, 20 min after injection, the transcytotic endosomes showed a marked enrichment in 5'-nucleotidase and especially in alkaline phosphodiesterase I. The results confirm the heterogeneity of rat liver endosomes and substantiate the concept of distinct endosomal compartments.
为了标记通过肝细胞进行跨细胞转运（转胞吞作用）所涉及的囊泡，将聚合免疫球蛋白A（pIgA）与辣根过氧化物酶（HRP）偶联，并注射到大鼠体内。注射后10或20分钟，通过二氨基联苯胺诱导的密度转移程序分离含有这种配体的内体，并测量其各种标记酶的含量。注射后10分钟携带pIgA-HRP的内体仅含有微量的5'-核苷酸酶和少量的碱性磷酸二酯酶I。估计的标记酶含量与观察到的含有与HRP偶联的半乳糖基化牛血清白蛋白的颗粒相似，HRP是一种在溶酶体中降解的配体。然而，注射后20分钟，转胞吞内体显示出5'-核苷酸酶明显富集，尤其是碱性磷酸二酯酶I。结果证实了大鼠肝内体的异质性，并证实了不同内体区室的概念。
