[Peroxidase properties of sheep haptoglobin complexes with hemoglobins of various types of animals].

It was found that haptoglobins from adult sheep and sheep foetus form active saturated complexes with sheep, cow, horse, mouse and human haemoglobins and with sheep foetus haemoglobin. This suggests that haemoglobin binding to haptoglobin does not depend on the species. The increase in the peroxidase activity during complex formation occurs in case of all haemoglobins; however, the degree of this increase is variable. This is probably due to the fact that during complex formation the haemoglobin molecule is stabilized, but no activation of Hb occurs. It can be assumed that the sites of the haptoglobin and haemoglobin molecules responsible for complex formation are relatively conservative in the course of evolution because of the physiological significance of the complex formation reaction.