Association of Bile‐Salt‐Dependent Lipase with Membranes of Human Pancreatic Microsomes

摘要: Immunolocalization studies indicated that, in contrast to other enzyme markers of human pancreatic secretion, bile-salt-dependent lipase (BSDL) was partly but specifically associated with endoplasmic reticulum membranes. In microsomes, temperature-induced phase separation using Triton X-114 elucidated the partition BSDL between aqueous and detergent-rich containing hydrophilic membrane proteins, respectively. The size membrane-associated (approx. 100 kDa) is compatible that fully processed enzyme. Fucosylated O- N-linked oligosaccharide structures were detected by means specific lectins. might therefore be released from membranes trans-Golgi compartment (where terminal fucose residues added) zymogen granules where mainly found soluble fraction. Even though enzymically active, it appeared less efficient than form. association pH-dependent optimal occurred pH 5–6. KBr which suggests microsomal involves ionic interactions. Lipid–protein interactions are probably not involved this as did associate liver microsome We attempted characterize putative ligand showed a 94-kDa protein, immunologically related glucose-regulated protein 94 kDa (Grp94), co-immunoprecipitated antibodies directed against each individual species. It suggested biogenesis an intracellular its folding may assisted molecular chaperones.