Open AccessMarker enzymes in rat liver vesicles involved in transcellular transport
Author(s) -
QUINTART Joël,
BAUDHUIN Pierre,
COURTOY Pierre J.
Publication year - 1989
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1989.tb15051.x
Subject(s) - endosome , transcytosis , horseradish peroxidase , vesicle , chemistry , alkaline phosphatase , biochemistry , paracellular transport , transcellular , enzyme , phosphodiesterase , bovine serum albumin , microbiology and biotechnology , biology , endocytosis , membrane , receptor , permeability (electromagnetism)
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.