Biological antifreezes constitute a diverse class of proteins found in arctic and antarctic fish, as well as in amphibians, trees, plants, and insects. These compounds are unique in that they have the ability to inhibit the growth of ice and consequently are essential for the survival of organisms inhabiting environments where sub-zero temperatures are routinely encountered. This is an unusual ability attributed only to biological antifreezes. There are two types of biological antifreezes, the antifreeze proteins (AFPs) and the antifreeze glycoproteins (AFGPs).[1] Antifreeze proteins are divided into four subtypes (types 1±4) each possessing a very different primary, secondary, and tertiary structure. In contrast, AFGPs are subject to considerably less structural variation. A typical AFGP is composed of a repeating tripeptide unit (threonyl±alanyl±alanyl) in which the secondary hydroxy group of the threonine residue is glycosylated with the disaccharide β-D-galactosyl-(1, 3)-α-D-N-acetylgalactosamine (Figure 1). Eight distinct AFGP subtypes exist; glycoproteins of 20±33kDa are referred to as AFGPs1±4 and those of less than 20kDa constitute AFGPs5±8. The lower molecular weight