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Identification of a Novel Glycosaminoglycan Core-like Molecule II

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Relation http://ir.cftri.com/1622/
JBC-11-95
 
Title Identification of a Novel Glycosaminoglycan Core-like Molecule II
 
Creator Salimath, P. V.
Spiro, Robert C.
Hudson, H. Freeze
 
Subject 16 Protein Biochemistry
 
Description The accompanying article (Manzi, A., Salimath, P. V., Spiro, R. C., Keifer, P. A., and Freeze, H. H. (1995) J. Biol. Chem. 270, 9154-9163) reported the complete structure of a novel molecule made by human melanoma cells incubated with 1 m M 4-methylumbelliferyl-Xyl (XylMU). The product resembles a common pentasaccharide core region found in chondroitin/dermatan sulfate glycosaminoglycans, except that a terminal -GalNAc residue is found in a location normally occupied by -GalNAc in these chains or -GlcNAc in heparan sulfate chains. In this paper we show that several other human cancer cell lines and Chinese hamster ovary cells also make -GalNAc-capped xylosides. The [6-H]galactose-labeled XylMU product binds to immobilized -GalNAc-specific lectin from Helix pomatia and the binding is competed by GalNAc, but not by Glc. Binding to the lectin is destroyed by digestion with - N-acetylgalactosaminidase, but not -hexosaminidase. The nature of the aglycone influences the amount and relative proportion of this material made, with p-nitrophenyl--xyloside being a better promoter of -GalNAc-terminated product than XylMU. This novel oligosaccharide accounts for 45-65% of xyloside-based products made by both human melanoma and Chinese hamster ovary cells when they are incubated with 30 ยต M XylMU, but at 1 m M both the total amount and the proportion decreases to only 5-10%. In both cell lines this product is replaced by a corresponding amount of Sia2,3Gal4XylMU. Preferential synthesis of the -GalNAc-capped material at very low xyloside concentration argues that it is a normal biosynthetic product and not an experimental artifact. This pentasaccharide may be a previously unrecognized intermediate in glycosaminoglycan chain biosynthesis. Since this -GalNAc residue occurs at a position that determines whether chondroitin or heparan chains are added to the acceptor, it may influence the timing, type, and extent of further chain elongation.
 
Date 1995-04
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
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Identifier http://ir.cftri.com/1622/1/JBC_270_9164_-_9168_1995.pdf
Salimath, P. V. and Spiro, Robert C. and Hudson, H. Freeze (1995) Identification of a Novel Glycosaminoglycan Core-like Molecule II. Journal of Biological Chemistry, 270 (16). pp. 9164-9168.