[Purification and chemical characterization of pregnancy-specific beta 1-glycoprotein (SP1)].

A pregnancy-specific beta 1-glycoprotein (SP1) was purified from human placenta using either an ion-exchange column [method I] or an anti-SP1 antibody immunoadsorbent column [method II]. The yields were 5.2% with a total of 1.2 mg per placenta [method I], and 9. 4% with a total of 2.2 mg per placenta [method II], respectively. The physicochemical properties (molecular weight, sedimentation coefficient, amino acid composition etc.) of SP1 purified from human placenta by these methods are essentially the same as those of typical SP1. It is thus apparent from the present results that these SP1 from pregnant serum and human placenta cannot be distinguished immunologically and biochemically.