Purification and properties of bullfrog prolactin.

Abstract
Prolactin was purified from bullfrog adenohypophyses by extraction of acetone-dried powder with acid acetone and chromatography on DEAE-cellulose and Sephadex G100. The bullfrog prolactin had a MW of 23,000 as determined by sodium dodecyl sulfate gel electrophoresis. The isoelectric point was 5.76 when determined by electrofocusing. The amino acid composition of the purified prolactin closely resembles that of mammalian prolactin. The prolactin was 3.6 times as potent as bovine prolactin in promoting collagen synthesis in the tadpole tail fin.