[Several approaches to purifying rat liver G2-chalone].

An attempt was made to isolate the liver tissue chalone blocking the transition of hepatocytes from G2 period of the cell cycle into mitosis/g2-chalone/. The purification was carried out using gel filtration through Sephadex G-75 and hydroxyapatite chromatography as well as by means of ultrafiltration through Diaflo membranes XM-300, XM-100 and PM-10. The biologically active preparation, obtained by these two procedures, was purified 100-fold. Molecular mass of G2 chalone was apparently less then 10,000; it penetrated through PM-10 membrane. The chalone appears to form complexes with high molecular carriers.