Keratan Sulfate Gal-6-Sulfotransferase
Keratan sulfate (KS) is composed of the repeating disaccharide unit of Galβ1-4GlcNAc (poly-N-acetyllactosamine) with sulfate groups at the 6-position of the Gal and GlcNAc residues. Most GlcNAc residues and half of the Gal residues of corneal KS are sulfated, suggesting that sulfation of the Gal residue occurs after sulfation of the GlcNAc residue and determines the extent of sulfation of KS. Keratan sulfate Gal-6-sulfotransferase (KSGal6ST) catalyzes the transfer of sulfate to position 6 of the Gal residue of KS. Therefore it has been thought that KSGal6ST is responsible for producing the highly sulfated type of KS. KSGal6ST is also able to sulfate sialyl N-acetyllactosamine oligosaccharides. KSGal6ST may be engaged in the biosynthesis of not only KS but also glycoproteins bearing sulfated sialyl N-acetyllactosamine or sulfated sialyl Lewis X oligosaccharides.
KeywordsSynaptic Vesicle Keratan Sulfate Synaptic Vesicle Protein GlcNAc Residue Repeat Disaccharide Unit
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