[Effects of various factors on the formation and properties of sheep haptoglobin-hemoglobin complexes].

The effects of pH, urea, Na-DS and various ions on the hemoglobin-binding capacity of haptoglobin (Hp) of sheep and on the properties of the Hb-Hp complex were studied. It was found that the optimal conditions for the Hb-Hp complex formation are pH values within the range of 4.5--7.0. The peroxidase activity of the complex has its maximum at pH 4.3. A comparative study of the stabilizing effects of Hp from sheep and other species on the hemoglobin molecule was carried out. It was suggested that the properties of the Hm-Hp complex depend on specific differences of haptoglobin within the complex. Urea, Na-DS and sulfate ions produce an inactivating effect, while tetraborate anions--an activating effect on the formation and stability of the complex. This is probably due to the interaction of these compounds with the Hp molecule which changes Hp reactivity and the properties of the Hb-Hp complex.