Biochemical Adaptation to the Freezing Environment — Structure, Biosynthesis and Regulation 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 2 decades, two entirely different animal groups have been investigated for their ability to survive at subzero temperatures. There are the marine fishes inhabiting the ice-laden seawater of the polar regions (Feeney and Yeh 1978; Ananthanarayanan and Hew 1978; DeVries 1982) and the overwintering terrestrial arthropods (Duman 1982). In order to survive, these organism have evolved mechanisms which include seasonal migrations to warmer and/or deeper waters, increased concentrations of glucose, glycerol, sorbitol, and other small molecules. Some organisms also appear to survive in a super-cooled state (Scholander et al. 1957). However, the most intriguing mechanism is the occurrence of an unique class of serum proteins which specifically lowers the freezing temperature below that of the surrounding environment. These proteins, commonly known as antifreeze proteins, have many interesting features. However, in the present communication, only the structural and biosynthetic aspects of these macromolecules from the marine fishes will be discussed.