Ph Effect on Thermal Transition Temperature of Collagen

ABSTRACT Differential scanning calorimetry (DSC) was used to measure the thermal transition temperature of bovine intramuscular and tendon collagen. Equilibration of the collagen in buffers in the pH range 4.25–7.40 resulted in a decline in transition temperature with decreasing pH. This was more pronounced in collagen with higher concentrations of aldimine crosslinks. We proposed that postmortem pH decline was responsible for the thermal transition temperature decline observed by other workers. Therefore, thermal transition temperature measurements must be performed on collagen samples that have been thoroughly equilibrated to a common pH if they are to be used as indices of structural changes.