Purification of alpha1-fetoprotein

Previously published methods for purifying alpha1-fetoprotein are inadequate because they either do not yield a completely pure product or they cause some denaturation. We present a method that does not have these serious disadvantages, and with which alpha1-fetoprotein was purified by sequential use of concanvalin A affinity-chromatography, preparative gel-electrophoresis, and immunoabsorption with anti-albumin antibody covalently coupled to Sepharose 4B. The purity of the product was monitored by discontinuous polyacrylamide-gel electrophoresis and counterimmunoelectrophoresis, both of which must be used to ascertain what proteins are present at each step of the purification.