Bi-antennary oligo-(N-acetyllactosamino)glycans of I-type are galactosylated preferentially at the GlcNAc beta 1-6Gal linked arms by alpha 1,3-galactosyltransferase of bovine thymus.
alpha 1,3-Galactosylation of radiolabelled bi-antennary acceptors Gal beta 1-4GlcNAc beta 1-3(Gal beta 1-4GlcNAc beta 1-6)Gal-R (R = 1-OH, beta 1-4GlcNAc or beta 1-4Glc) with bovine thymus alpha 1,3-galactosyltransferase was studied. At all stages of the reactions the three acceptors reacted faster at the 1-->6 linked arm than at the 1-->3 linked branch. Hence, in addition to the doubly alpha 1,3-galactosylated products, practically pure Gal beta 1-4GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal-R could be obtained from the three acceptors in reactions that had proceeded to near completion. The isomeric mono-alpha 1,3-galactosylated products were identified by using exoglycosidases to remove the branches unprotected by alpha 1,3-galactoses and by subsequently identifying the resulting linear glycans chromatographically.
Seppo
A
A
Institute of Biotechnology, University of Helsinki, Finland.
Penttilä
L
L
Leppänen
A
A
Maaheimo
H
H
Niemelä
R
R
Helin
J
J
Wieruszeski
J M
JM
Renkonen
O
O
D000818:Animals; D002240:Carbohydrate Sequence; D002417:Cattle; D005690:Galactose / Q000378:metabolism*; D005700:Galactosyltransferases / Q000378:metabolism*; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000378:metabolism*; D013950:Thymus Gland / Q000201:enzymology*
D011134:Polysaccharides; D005700:Galactosyltransferases; C037959:beta-D-galactosyl-N-acetylglucosaminylglycopeptide alpha-1,3-galactosyltransferase; D005690:Galactose