Electrical conduction in collagen. II. Some aspects of hydration

Determinations of the amount of bound water in hydrated proteins yield strongly diverging values. The cause of this is the continuity of the transition from bound to free water, and the diffeernt sensitivities to water structure of the measuring techniques. Only the methods that aim at the determination of the amount of water, whose phase remians unchanged duing freezing, yield similar values. The value for collagen as deduced from conductivity data is about 50% water of the dry weight. It is believed that this water interacts with adsorptive groups on the macromolecules, whereas the freezable water occurs in capillaries.