Plasticity of two structural proteins: Alpha-collagen and beta-keratin

Although the microstructures of Type-I collagen in bone and F-keratin in avian feathers are very different, their plastic behaviour is similar. In both plasticity is thermally activated, with the activation enthalpy H=1.1eV in bone and 1.75 eV in feather. The activation volumes are v=0.6nm3 in bone and v=0.83nm3 in feather. This indicates that the rate controlling process in both is the breaking of electrostatic bonds.