Isolation and partial molecular characterization of heat-stable growth factor from human placenta

A heat-stable growth factor has been purified to homogeneity from human pla centa. Purification procedure involved extraction with acidic medium, preci pitation using ethanol, DE-52 ion-exchange chromatography, and reversed-pha se HPLC. The purified preparation has been named human placental growth fac tor-1 (HPGF-1), which simulates the proliferation of some cell lines, such as human amniotic cell, mouse marrow tumor cell, and mouse fibroblast cell. The growth factor has an approximate molecular weight of 1 900. It is a gl ycopeptide which contains a polypeptide chain consisting of 10 amino acid r esidues with molecular weight of 1 195. The N-terminal residue of the polyp eptide chain part is phenylalanine. The molecular weight of non-peptide par t is 682. The isoelectric point of the growth factor is pI 6.8.