Sugar chains of serum transferrin from patients with carbohydrate deficient glycoprotein syndrome. Evidence of asparagine-N-linked oligosaccharide transfer deficiency

• Published in: The Journal of biological chemistry Vol. 268; no. 8; pp. 5783 - 5789
• Main Authors: YAMASHITA, K, IDEO, H, OHKURA, T, FUKUSHIMA, K, YUASA, I, OHNO, K, TAKESHITA, K
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 15.03.1993
• Subjects: Analytical, structural and metabolic biochemistry; Asparagine - metabolism; Biological and medical sciences; carbohydrate deficient glycoprotein syndrome; Carbohydrate Metabolism, Inborn Errors - metabolism; Carbohydrate Sequence; Carbohydrates; chains; Chromatography, Affinity; Chromatography, Gel; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Humans; Isoelectric Point; isoforms; Lectins; man; Metabolism, Inborn Errors - blood; Metalloproteins; Molecular Sequence Data; Oligosaccharides - blood; Oligosaccharides - chemistry; Other metalloproteins; Proteins; sugar; Syndrome; transferrin; Transferrin - chemistry; Transferrin - isolation & purification; Transferrin - metabolism; Human; Ferroprotein; Molecular form; Transferrin; Primary structure; Carbohydrate chain; Chromatofocusing
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)53387-1

The structure of over 93% of the sugar chains of serum transferrin purified from three patients with carbohydrate-deficient glycoprotein (CDG) syndrome was Neu5Ac alpha 2-->6Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->6 (Neu5Ac alpha 2-->6Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->3)Man beta 1-->4GlcNac beta 1-->4GlcNAc, similar to that in a healthy control. On chromatofocusing, CDG syndrome transferrin was separated into three major isoforms, S4, S2, and S0, containing 4, 2, and 0 sialic acids/molecule at pH 5.12 (5.16), 5.42, and 5.80, respectively. On 7.5% SDS-polyacrylamide gel electrophoresis, the molecular masses of transferrin isoforms S4, S2, and S0 were 80, 77, and 74 kDa, respectively. Transferrin isoforms S4 and S2 were linked to 2 and 1 mol of sialylated biantennary sugar chain/transferrin molecule, on the other hand, isoform S0 was not linked to any asparagine-N-linked oligosaccharide. Accordingly, CDG syndrome can be concluded to be an asparagine-N-linked oligosaccharide transfer deficiency, although the primary deficient enzyme has not yet been determined.