PARAMETERS OF HEAT DESTRUCTION OF COLLAGE N NATIVE STRUCTURES AND ITSRELATION TO THE BIOLOGICAL AGE

By means of differential scanning calorimetry we have studied the infl uence of structural changes induced by the biological aging on the pro cesses of thermal denaturation of collagen tissue (rat tail tendon, ag e from 14 days to 24 months). We have found that some parameters of th e thermal denaturation process, namely, the denaturation temperature T -d and the denaturation heat Q(d) are sensitive to the biological age or the tissue. Both T-d and Q(d) are increasing with the age. However, this increase takes place only on early stages of aging. When the den aturation heat Q, of the tissue is normalized on the content of collag en in it, one obtains the independent on the age value of 75 J/g. So t he increase of Q(d) with aging reflects the increase of the collagen c ontent in tissue. We have found that the half-widths of the denaturati on curves Delta T-1/2 as well as the heat capacity increment at denatu ration Delta C-p do not depend on the tissue age. Both for fibrills of collagen and for its solution the measured value of Delta C-p is equa l 0,42+/-0,004 J/g degrees C which differs considerably from the earli er published data.