11.2.1 Physical instabilityPhysical

11.2.1 Physical instability
Physical instability is a phenomenon which is rarely encountered with small organic mol- ecules but arises in peptides and proteins because of the many conditions under which
proteins can lose their native three- dimensional structure. Unfolding of stable forms can lead to adsorption, aggregation or further chemical reactivity. Aggregation can lead to precipitation. Loss of the unique bio- logically active three-dimensional structure (i.e. denaturation), can be caused by heating and, conversely, by cooling or freezing, extremes of pH, and contact with organic chemicals and denaturants. Most of these act through their influence on solubility or confor- mation, hence the importance of understand- ing protein