Pregnancy-specific beta 1-glycoprotein (SP1). Purification and partial characterization.

The pregnancy-specific beta 1-glycoprotein, SP1, was purified to homogeneity from placental extract and from serum using immunoadsorbent techniques. The isolated SP1 had a molecular weight of 90,000-110,000 daltons and an amino acid and amino sugar composition typical of an acidic glycoprotein. The availability of purified SP1 will be of value in the further evaluation of the role and importance of SP1 in malignancies as well as in normal development.