IDENTIFICATION AND REMOVAL OF POLYMER-FORMING AND AGGREGATE-FORMING PROTEINS IN HUMAN PLASMA-ALBUMIN PREPARATIONS

The presence of the glycoproteins haptoglobin and hemopexin in human p lasma albumin (HPA) solutions were demonstrated to be responsible for the formation of polymers and aggregates during heat treatment for 10 h at 60 degrees C. Apart from haptoglobin and hemopexin three other co ntaminating proteins were identified as transferrin, Gc-globulin and b eta(2)-glycoprotein. During heat treatment the antigenicity of haptogl obin and hemopexin changed markedly and more than 90% of the antigens appeared as aggregates in the void volume during the following size ch romatography. Without loss of albumin haptoglobin and hemopexin were r emoved from the HPA preparation by lectin (concanavalin A) affinity ch romatography. The haptoglobin- and hemopexin-depleted HPA preparation did not form aggregates or polymers during heat treatment.