The Degradation of Collagen. A Method for the Characterization of Native Collagen

The dye-protein precipitation method for the estimation of polar functional groups on the protein has been applied to an investigation of a highly purified bovine hide collagen and several mildly degraded collagens. There is no difference in the maximum number of basic dye binding sites on each sample per unit weight, but the concentration dependence of the binding is clearly related to the extent of degradation. Less than half of the theoretically available anionic groups are available as dye binding sites in the undegraded material. These become available in stages as the extent of degradation is increased. The thermodynamic functions ΔF° and ΔS ° have been evaluated for the combination of the undegraded protein with Orange-G and Safranin-O.