The size of the C-chain maltosaccharide of glycogen: evidence for the presence of only a single branch.
Glycogen is found in mammals and yeast bound to glycogenin forming proteoglycogen. The branched polysaccharide is joined to the protein through the C-chain, a maltosaccharide considered to be 13 glucose units long and double branched as the other branched glycogen B-chains. We described before the isolation of c-glycogenin, the debranched C-chain bound to glycogenin, from muscle proteoglycogen. In this work, the size of the C-chain is analyzed for the first time. The maltosaccharide moiety of c-glycogenin was auto[14C]glucosylated by a short incubation with UDP-[14C]glucose, and the labeled maltosaccharide was released by heating in 2 M NaOH containing 0.1 M NaBH4 and analyzed by high-performance thin layer chromatography (HPTLC). The results indicate that the C-chain is about half the size of the B-chains, not long enough to be double branched.
Bazán
Soledad
S
Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), UNC-CONICET, Departamento de Química Biológica DrRanwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
Curtino
Juan A
JA
D002855:Chromatography, Thin Layer; D006003:Glycogen / Q000737:chemistry*; D008320:Maltose / Q000737:chemistry*; D025942:Oligosaccharides, Branched-Chain / Q000737:chemistry*
D025942:Oligosaccharides, Branched-Chain; D008320:Maltose; D006003:Glycogen