Apolipoprotein H is a single chain polypeptide composed of 326 amino acids highly glycosylated. Its carbohydrate content is approximately 19% of the molecular weight. We show that it is rich in sialic acid linked alpha (2-6) to galactose or N-acetylgalactosamine. Sialic acid is not alpha (2-3) linked to galactose. Galactose is beta (1-4) linked to N-acetylglucosamine and beta (1-3) linked to N-acetylgalactosamine. Carbohydrate O-linked chains (mainly sialic acid) are alpha (2-6) linked to galactose or N-acetylgalactosamine. Galactose is also organised in O-linked chains and beta (1-4) linked to N-acetylglucosamine and beta (1-3) linked to acetylgalactosamine. Concanavalin A lectin was used to isolate two groups of apolipoprotein H molecules bearing biantennary and truncated hybrids and high mannose and hybrid oligosaccharides. Apolipoprotein H fails to bind lysine-Sepharose. Our results thus show that it presents truncated hybrid or hybrid-type carbohydrate chains which bear few unmasked mannose residues as a terminal sugar. Biochemical analysis of carbohydrate structures conducted on single isoforms separated through IEF revealed that no specific carbohydrate complex is bound to a single isoform.
Titolo: | Study of the glycosylation of apolipoprotein H. |
Autori Riconosciuti: | |
Autori: | GAMBINO R ;RUIU G ;PAGANO G ;CASSADER M |
Data di pubblicazione: | 1999 |
Abstract: | Apolipoprotein H is a single chain polypeptide composed of 326 amino acids highly glycosylated. Its carbohydrate content is approximately 19% of the molecular weight. We show that it is rich in sialic acid linked alpha (2-6) to galactose or N-acetylgalactosamine. Sialic acid is not alpha (2-3) linked to galactose. Galactose is beta (1-4) linked to N-acetylglucosamine and beta (1-3) linked to N-acetylgalactosamine. Carbohydrate O-linked chains (mainly sialic acid) are alpha (2-6) linked to galactose or N-acetylgalactosamine. Galactose is also organised in O-linked chains and beta (1-4) linked to N-acetylglucosamine and beta (1-3) linked to acetylgalactosamine. Concanavalin A lectin was used to isolate two groups of apolipoprotein H molecules bearing biantennary and truncated hybrids and high mannose and hybrid oligosaccharides. Apolipoprotein H fails to bind lysine-Sepharose. Our results thus show that it presents truncated hybrid or hybrid-type carbohydrate chains which bear few unmasked mannose residues as a terminal sugar. Biochemical analysis of carbohydrate structures conducted on single isoforms separated through IEF revealed that no specific carbohydrate complex is bound to a single isoform. |
Volume: | 103 |
Pagina iniziale: | 161 |
Pagina finale: | 174 |
Rivista: | CHEMISTRY AND PHYSICS OF LIPIDS |
Appare nelle tipologie: | 03A-Articolo su Rivista |
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