Polylactosamine

Plaas AHK, Wongpalms S. Biosynthetic mechanisms for the addition of polylactosamine to chondrocyte libromodulin. J. Biol. Chem. 1993 268(35) 26634-26644. 

Complex-type structures have 2-4 lactosamine (Gal /Jl,4-Gn) units distributed over the two outer Man residues of the core forming bi-, tri-, or tetra-antennary structures. Each of the arms can terminate in sialic acid forming sialyllactosamine. Sulfated lactosamine has been found to substitute sialyl-lactosamine in some cases, such as the glycoprotein hormones EH, FSH and TSH. Other complex-type structures contain polylactosamine in their outer chains, as in erythroglycan. 

Fig. 16. Branching patterns and presence of polylactosamine in complex-type N-glycans of laminin fragments. Data from Fujiwara et al. [289]. Each structure is variably terminated with sialie acid and/or a-galactosyl residues. R is Man 31-4GlcNAcPl-4GlcNAc Fucal-6 core residues.

L-Fucose may be present in O- and N-glycosylic chains of glycoproteins.85 Polylactosamine chains in O- or N-linked glycans of glycoproteins, or in gly-cosphingolipids, may be modified by attachment of fucose residues, giving rise to blood-group determinants.205... 

Velupillai P, Secor WE, Horauf Ham AM. B-1 cell (CD5+B220+) outgrowth in murine schistosomiasis is genetically restricted and is largely due to activation by polylactosamine sugars. J Immunol 1997 158 338-344. 

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