Structure and Function of Fish Antifreeze Polypeptides

Abstract

The ability of many organisms to survive in cold environments is of considerable scientific interest and importance. During the past two decades/ two entirely different animal groups have been investigated for their ability to survive at subzero temperatures. These are the marine fishes inhabiting the ice-laden sea water of the polar regions (1,2,3) and the overwintering terrestrial arthropods (4). Generally, the members of these groups that do not undertake a seasonal migration to warmer environments produce serum antifreezes. These may be the macromolecular antifreezes; (glycoproteins and polypeptides) found in fishes and some insects, or the colligative antifreezes such as glucose, glycerol, sorbitol and other small molecules that are common in the latter group. Some organisms also appear to survive in a super-cooled state (5). In the present communication, only the structural and functional aspects of antifreeze proteins from the marine fishes will be discussed.