[Estradiol-binding properties of a sheep haptoglobin complex with hemoglobin. II. Preliminary data on quantitative characteristics of interaction]. / Estradiolsviazyvaiushchie svoistva kompleksa gaptoglobina ovtsy s gemoglobinom. II. Predvaritel'nye dannye po kolichestvennoi kharakteristike vzaimodeistviia.

The estradiol-binding properties of the sheep haptoglobin-hemoglobin complex (Hp-Hb) have been studied. The time and temperature dependencies of the steroid binding have been established the tightly bound 17 beta-estradiol, which is not detached from the complex during precipitation or extraction, has been shown to form a part of the total amount of the steroid capable of bending to Hp-Hb. Disturbances in the protein-protein interactions between Hp and Hb lead to the dissociation of estradiol as well as to the loss by the protein of its estradiol-binding activity. The values of relative competitive activity for several steroids suggest that some structural elements of the 17 beta-estradiol molecule play a role in estradiol-protein interactions. It is assumed that the Hp-Hb complex has two or more 17 beta-estradiol binding sites.

[17 Beta-estradiol interaction with haptoglobin and its complex with hemoglobin]. / Issledovanie vzaimodeistviia 17 beta-éstradiola s gaptoglobinom i egokompleksom s gemoglobinom.

The estradiol-binding capacity of sheep haptoglobin and its complex with hemoglobin was investigated. It was shown that in the presence of H2O2 the haptoglobin-hemoglobin complex tightly binds 17 beta-estradiol. No dissociation of the estradiol-protein complex occurs after its precipitation with trichloroacetic acid and steroid extraction with the ester. It is supposed that the 17 beta-estradiol is bound to the protein by covalent bonds; this binding is characteristic only of the haptoglobin-hemoglobin complex but not of haptoglobin alone.