A novel procedure for the purification of bovine somatomedin.

Abstract

A procedure for the partial purification of bovine somatomedin (SM) is presented. SM from serum is adsorbed to small pieces of chicken cartilage by exposure of cartilage to serum at room temperature. After 8 h of exposure, the serum is removed and the SM activity adsorbed to the cartilage is recovered by extraction of cartilage with 1.5 M NaCl. The salt extract is centrifuged to remove most of a polysaccharide contaminant and then is dialyzed and concentrated by freeze-drying. Polyacrylamide disc electrophoresis of this material reveals a major zone of SM activity possessing slight anodal migration and a second minor active peak exhibiting marked anodal mobility. The potency of SM so isolated is about 2500-fold more active than native serum and possesses 40–50% of the initial SM activity. The material obtained prior to acrylamide electrophoresis retains about 50% of its activity after 5 months of storage at 6°.It is suggested that this procedure could be of benefit as an initial purification prior to the employment of the classical purification procedures. As this method can be modified readily to accommodate large volumes of serum, it would be possible to isolate milligram quantities of SM for studies in which its chemical and biochemical properties can be elucidated.