Determination of the primary structures of 16 asialo-carbohydrate units derived from human plasma α1-acid glycoprotein by 360-MHz proton NMR spectroscopy and permethylation analysis
Year: 1978
Type: article
Abstract: The present study was initiated in order to determine \nthe primary structures of the carbohydrate units of \ndesialyzed human plasma al-acid glycoprotein. In an earlier \ninvestigation I6 glycopeptides which originated from four of \nthe five glycosylation sites of this protein were prepared in the \nhomogeneous state. Since the elucidation of the structures of \nsuch a large number of carbohydrate units by the conventional \nchemical and enzymatic procedures would require a very long \nperiod of time and considerable amounts of material, a new \nmethod-360-MHz H NMR spectroscopy-in combination \nwith methylation analysis and partial acetolysis was introduced \ni n the present study. This highly sensitive method allowed the \nelucidation of the structures of the carbohydrate units of the \nmentioned glycopeptides to be carried out in a very short period of time. The present investigation revealed that the structures \nof the 16 heteroglycans can be grouped into five classes, and, \nexcept for those of two classes, the structures are new. Two \nclasses designated A and B possess the known bi- and trimtennary \nstructures, respectively. A third class designated C \nproved to be tetraantennary in its structure, whereas the other \nclasses designated BF and CF are, in comparison with the \nstructures of classes B and C, characterized by an additional \nfucose residue in a hitherto unknown position and linkage. \nThe latter monosaccharide residue is attached in an a( 1-3) \nbond, vicinal to Gal@(1 +4), to the GlcNAc residue 7. The \npresent study also revealed that each glycosylation site of \npooled a]-acid glycoprotein possesses carbohydrate units with \ndifferent structures.
Source: Biochemistry
DOI: 10.1021/bi00617a021
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2084037895