[A comparative study of pregnancy-associated protein A and its analogs in animals]

Glycoproteins similar in composition, structure, and functions were isolated from the blood serum of pregnant women, cows, dogs, and rats. They consist of four identical subunits, which form dimers due to covalent bonds, while dimers form tetramers due to hydrogen bonds. All these proteins are non-specific inhibitors of proteases and bind these enzymes in the same way as alpha-macroglobulins do, by capture in a "trap". Furthermore, they are capable of binding and transporting various cytokines. The results obtained indicate that these proteins belong to the family of macroglobulins.