Molecular Structures And Antifreezing Mechanism Of Fish Antifreeze Polypeptides And Glycoproteins

Many living beings can exist in the bitter cold circumstance. In polar and subpolar areas of the ocean, fish may live in water as cold as -1.9℃ (the freezing temperature of sea water). The reason of these fishes having antifreezing properties is that antifreeze polypeptides (are termed as ice growth inhibitors) in the blood serums of these fishes can lower the freezing temperatures. Four distinct macromolecular antifreezes have been isolated and characterized from different marine fishes. These include the antifreeze glycoproteins(AFGPs) and three antifreeze protein (AFPs) types.Despite the marked differences in amino acid composition and protein structure between these macromolecular antifreeze types, they all appear to interact with ice in the similar way, and they all have antifreeze function and thermal hysteresis behavior in the process of freezing.In this study, the secondary structures of these different types of antifreeze polypeptides are investigated by the theoretical methods, and the peculiarity of the tertiary structure of the AFPs are...