ROLE OF PROCESSING OF THE OLIGOSACCHARIDE CHAINS IN THE AFFINITY OF LIPOPROTEIN-LIPASE FOR HEPARIN

The role of processing of the oligosaccharide chains in the affinity o f lipoprotein lipase (LPL) for heparin was examined in 3T3-L1 adipocyt es. 43% of S-35-labeled LPL subunits in tunicamycin (TUN)-treated cell s did not bind to a heparin-Sepharose column and 46% was eluted with 0 .6 M NaCl. 11% of LPL subunits in castanospermine (CSTP)-treated cells did not bind to the column and 38% was eluted with 0.6 M NaCl. In con trast, as in untreated cells, LPL subunits in 1-deoxymannojirimycin (d MM)-treated and swainsonine (SW)-treated cells almost all bound to the column and over 93% of the subunits bound were eluted with 1.5 M NaCl . Thus, core glycosylation and subsequent removal of the distal glucos e residue from oligosaccharide chains of LPL in the endoplasmic reticu lum (ER) is required for acquisition of a higher affinity for heparin.