Fish glycopeptide and peptide antifreezes: their interaction with ice and water

Glycopeptide and peptide antifreeze agents are present in the body fluids of polar fishes and allow them to avoid freezing in ice-laden seawater. These antifreezes lower the freezing point 200 times more than predicted by colligative relations, but have little effect on the melting point of ice. They bind to ice and appear to inhibit growth by increasing the curvature of growth steps on the ice crystal surface. Such a growth would result in a substantial increase in the roughness of the surface of the crystal. Laser light scattering techniques have been used to evaluate the dependence on temperature of the surface roughness at the ice/antifreeze solution interface. Results show a dramatic increase in scattered light as the temperature is decreased toward the freezing point of antifreeze solutions.