Title :
The polylactosaminoglycans of human lysosomal membrane
glycoproteins lamp-1 and
lamp-2
Abstract :
- Localization on the peptide backbones
- Lysosome membrane glycoproteins , lamp-1 and lamp-2 , have been shown to contain 18 and 16 N-glycans , some of which are modified by poly-N-acetyl-lactosamine
- We have localized the polylactosaminoglycans to specific sites on lamp-1 and lamp-2 purified from human chronic myelogenous leukemia cells
- Polylactosaminoglycan-containing glycopeptides , obtained by trypsin, pepsin, and V8 protease digestion of the glycoproteins , were isolated by Datura stramonium agglutinin affinity chromatography, gel filtration, and reverse phase high performance liquid chromatography
- The poly-N-acetyllactosaminyl structures of isolated glycopeptides were confirmed by the susceptibility of their released oligosaccharides to endo- beta-galactosidase
- Amino acid analysis and sequencing demonstrated that polylactosaminoglycans were located at Asn-34, Asn-93 and/or Asn-102, and Asn-195 and/or Asn-200 in lamp-1 , and at Asn-4 and/or Asn-10, and Asn-279 in lamp-2
- These results indicated that only certain glycosylation sites can be selectively modified by poly-N-acetyllactosamine , and those sites may confer the requirement by beta 1---- 3-N-acetylglucosaminyl transferase