[Biological function of the carbohydrate component of human sex hormone-binding globulin].

The role of the carbohydrate component of sex steroid-binding globulin (SBP) from human blood in the glycoprotein interaction with the recognition system for SBP-estrogen complexes in human decidual endometrium plasma membrane was studied. It was shown that the removal of N-acetylneuraminic acid residues from the oligosaccharide chains of SBP did not affect the steroid-binding or immunochemical properties of the glycoprotein. At the same time, the above modification of the glycoprotein resulted in a loss by SBP of its ability to specifically interact with the membrane recognition system. It is concluded that the oligosaccharide chains of SBP are involved in the formation of determinants needed for recognition of the SBP-estrogen complexes by endometrium cell plasma membranes.