title: Primary structure of the low-molecular-weight carbohydrate chains of Helix pomatia alpha-hemocyanin. Xylose as a constituent of N-linked oligosaccharides in an animal glycoprotein.
abstract: alpha-Hemocyanin of Helix pomatia is a copper-containing glycoprotein which serves as an oxygen carrier in the hemolymph. Its carbohydrate moiety has as constituents fucose, xylose, 3-O-methylgalactose, mannose, galactose, N-acetylgalactosamine, and N-acetyl-glucosamine residues. Alkaline borhydride did not split off any carbohydrate material, suggesting the absence of O-glycosidic chains. The N-glycosidic carbohydrate chains of this glycoprotein were liberated by hydrazinolysis of a Pronase digest then fractionated as alditols on Bio-Gel P-4. The fractions containing the low-molecular-weight glycans were investigated by 500-MHz 1H NMR spectroscopy in conjunction with sugar and methylation analysis. The largest, and most abundant, compound was established to be: (Formula: see text). Another compound was characterized as the afuco analogue of this structure. H. pomatia alpha-hemocyanin is the first example of an animal glycoprotein having xylose as a constituent of N-glycosidic carbohydrate chains.
mesh_terms: D000117:Acetylglucosamine / Q000032:analysis; D000818:Animals; D001894:Borohydrides / Q000494:pharmacology; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D005643:Fucose / Q000032:analysis; D006372:Helix, Snails / Q000032:analysis*; D006433:Hemocyanins / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000032:analysis; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis*; D011402:Pronase / Q000378:metabolism; D014994:Xylose / Q000032:analysis*
chemical_list: D001894:Borohydrides; D002241:Carbohydrates; D009844:Oligosaccharides; D005643:Fucose; D006433:Hemocyanins; D014994:Xylose; D011402:Pronase; D008358:Mannose; D000117:Acetylglucosamine