Structure of the carbohydrate units of IgA1 immunoglobulin: II. Structure of the O-glycosidically linked oligosaccharide units

J Baenziger, S Kornfeld - Journal of Biological Chemistry, 1974 - Elsevier
J Baenziger, S Kornfeld
Journal of Biological Chemistry, 1974Elsevier
In the preceding paper (B aenziger, J., and K ornfeld, S., J. Biol. Chem. 249, 7260–7269) the
structure of the two asparagine-linked oligosaccharide units of an IgA 1 myeloma protein
was defined. In this paper we present data which establish the structure and linkage points
of the five O-glycosidically linked oligosaccharide units found on the α 1 subtype heavy
chain to be as shown below.[see PDF for equation] This structure appears to be identical
with that which we have determined for the hinge region glycopeptide isolated by Frangione …
In the preceding paper (Baenziger, J., and Kornfeld, S., J. Biol. Chem. 249, 7260–7269) the structure of the two asparagine-linked oligosaccharide units of an IgA1 myeloma protein was defined. In this paper we present data which establish the structure and linkage points of the five O-glycosidically linked oligosaccharide units found on the α1 subtype heavy chain to be as shown below.
[see PDF for equation]
This structure appears to be identical with that which we have determined for the hinge region glycopeptide isolated by Frangione and Wolfenstein-Todel [Frangione, B., and Wolfenstein-Todel, C. (1972) Proc. Nat. Acad. Sci. U. S. A. 69, 3673–3676], from a different IgA1 myeloma protein. This region is deleted in the α2 subtype of IgA. Aside from the presence of a terminal N-acetylgalactosamine at the NH2 terminus, the location and structure of the 5 O-glycosidically linked oligosaccharide units of the glycopeptide preserve the symmetry observed by Frangione and Wolfenstein-Todel to be present in the amino acid sequence of the hinge region.
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