Open AccessStructure determination of the major N‐ and O‐linked carbohydrate chains of the β subunit from equine chorionic gondotropin
Author(s) -
DAMM Jan B. L.,
HÅRD Karl,
KAMERLING Johannis P.,
DEDEM Gijs W. K.,
VLIEGENTHART Johannes F. G.
Publication year - 1990
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1990.tb15474.x
Subject(s) - glycan , chemistry , asparagine , sialic acid , protein subunit , carbohydrate , biochemistry , stereochemistry , g alpha subunit , alpha (finance) , amino acid , glycoprotein , gene , medicine , construct validity , nursing , patient satisfaction
The carbohydrate moieties of equine chorionic gonadotropin α and β subunits were released from the protein backbones by successive treatments with peptide‐( N ‐acetyl‐β‐glucosaminyl)asparagine amidase F and alkaline borohydride and then fractionated by FPLC and HPLC. The major N‐ and O‐linked glycans of the β subunit were characterized by 500‐MHz 1 H‐NMR spectroscopy, showing a remarkable structural heterogeneity for the N ‐glycosidically linked chains, comprising mono‐,di‐, tri‐ and tri′‐antennary N ‐acetyllactosamine type of glycans, being partly α1‐6 fucosylated at the Asn‐bound GlcNAc residue and having α2‐6 and α2‐3 linked N ‐acetyl‐ and N ‐acetyl‐4‐ O ‐acetylneuraminic acid residues as sialic acid constituents. Significant differences in this respect were detected for the partially characterized glycans of the α subunit. The major part of the O‐linked carbohydrate chains, occurring solely in the β subunit, is formed by tri‐, tetra‐, penta‐ and hexa‐saccharides. There are indications for the presence of oligo( N ‐acetyllactosamine) units in both the N‐ and O‐linked glycans of the β subunit.