| Abstract: | Insulin binding of human erythrocytes has been investigated between 0 and 37 degrees C using porcine 125I-insulin/unlabeled porcine insulin and mono [125I] (Tyr-A14)biosynthetic human insulin/ unlabeled biosynthetic human insulin, respectively. Either system exhibited a regular thermodynamical behavior between 0 and 22 degrees C, giving unitary free-energy changes of about -58/ -59 kJ/mol, unitary entropy changes of about +55/ +70 J/K per mol and a reaction heat of -43.1/ -38.3 kJ/mol. From 22 up to 37 degrees C an irregular thermodynamical behavior could be observed, which can be partially explained by an increased insulin degradation during incubation and an additional time-dependent binding of the degradation products. |
