title: Antifreeze glycopeptides of the high-Antarctic silverfish Pleuragramma antarcticum (Notothenioidei).
abstract: Antifreeze glycopeptides (AFGP) have been isolated from the fully pelagic high-Antarctic silverfish Pleuragramma antarcticum of the suborder Notothenioidei (Perciformes). The fishes were caught during the PRV Polarstern expedition EPOS III (Jan-Mar, 1989) in the eastern and southeastern Weddell Sea. Glycoconjugate and amino acid analysis of antifreeze glycopeptides (AFGP) indicate that the glycopeptide structure is identical to the polymers of H2N[Ala-Ala(beta-galactosyl(1-->3)-alpha-N- acetylgalactosamine)Thr]nAla-Ala-COOH of previously studied Antarctic notothenioids. The content of AFGPs in P. antarcticum is lower than in other notothenioid fish from the same region. Antifreeze activity shows a maximal hysteresis of 1.19 degrees C at a concentration of 20 mg/ml AFGP. A linear increase in activity of the antifreeze glycopeptides could be demonstrated concomittant with a decreasing ice content. The freezing point of blood serum is -1.9 degrees C.
authors.affiliation: Institut für Polarökologie, Universität Kiel, Germany.
authors.forename: A P
authors.initials: AP
authors.lastname: Wöhrmann
mesh_terms: D000116:Acetylgalactosamine / Q000032:analysis; D000595:Amino Acid Sequence; D000818:Animals; D021301:Antifreeze Proteins; D002152:Calorimetry, Differential Scanning; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D005615:Freezing; D005690:Galactose / Q000032:analysis; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification*; D015151:Immunoblotting; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010473:Perciformes / Q000097:blood* / Q000502:physiology; D012623:Seawater
chemical_list: D021301:Antifreeze Proteins; D006023:Glycoproteins; D000116:Acetylgalactosamine; D005690:Galactose