title: Isolation and characterization of an asparagine-linked keratan sulfate from the skin of a marine teleost, Scomber japonicus.
abstract: Keratan sulfate was isolated from the skin of Pacific mackerel (Scomber japonicus) after exhaustive digestion with pronase followed by ethanol precipitation and fractionation on a cellulose column with 0.3% recovery of dried material. The keratan sulfate preparation was separated into four major fractions by Dowex-1 column chromatography. The chemical and infrared spectrum analyses of the four fractions showed a high degree of heterogeneity in sulfation. Since the carbohydrate-peptide linkage in the teleost skin keratan sulfate was found to be stable in alkali, and asparagine was the predominant amino acid, the asparagine residue in the peptide backbone was most likely to be involved in the N-glycosyl linkage with the carbohydrate moiety. Besides the type of carbohydrate-peptide linkage, the teleost skin keratan sulfate is very similar to corneal keratan sulfate (keratan sulfate I) in two respects: (1) The teleost skin and bovine corneal keratan sulfates were hydrolyzed much faster by endo-beta-galactosidase than the whale nasal cartilage keratan sulfate (keratan sulfate II). (2) Although the teleost skin keratan sulfate showed considerable polydispersity, the molecular weight was in the same range as the corneal keratan sulfate, and it was relatively higher than that of the cartilage keratan sulfate.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001216:Asparagine / Q000032:analysis*; D005399:Fishes; D006025:Glycosaminoglycans / Q000302:isolation & purification*; D006026:Glycoside Hydrolases; D006595:Hexosamines / Q000032:analysis; D006868:Hydrolysis; D007632:Keratan Sulfate / Q000302:isolation & purification*; D012867:Skin / Q000032:analysis*; D013045:Species Specificity; D013055:Spectrophotometry, Infrared; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D000596:Amino Acids; D006025:Glycosaminoglycans; D006595:Hexosamines; D001216:Asparagine; D007632:Keratan Sulfate; D006026:Glycoside Hydrolases; C026093:keratan-sulfate endo-1,4-beta-galactosidase; D001616:beta-Galactosidase