Stress-induced structure and activity changes in biologically active proteins

This review article attempts to bring some cohesion and focus to the efforts to understand the effects of mechanical forces on proteins, primarily enzymes. A sine qua non of the design of biomedical devices is that they minimize the effects of nonphysiological mechanical stresses on the proteins exposed to them. Conversely, in situations where other design constraints dictate the hydrodynamics, it is essential that data be available on the expected ramifications. While most of the available results deal with the effects of fluid shear stresses on proteins in solutions, other situations of interest include fluid shear stresses interacting with proteins at flow boundaries and deformation of solids containing enzyme activity. In addition to the type of deformation, the other factors essential to consider in assessing the significance of any study of stress effects on proteins are: (1) magnitude of applied stress; (2) magnitude of strain and/or strain rate; (3) duration of applied stress; (4) presence of solid/liquid or gas/liquid interfaces; (5) chemical environment; (6) molecular size, shape and structure of species and; (7) protein concentration in solution experiments. Each of these is shown to be a dominant factor in certain situations, and no single study to date may be said to have given proper consideration to all of them.