Purification of Human Placental Lactogen

Abstract

Human placental lactogen (HPL) of high specific activity has been isolated by modification of a previously reported procedure. Precipitation at pH 5 prior to gel filtration consistently removes 36% of protein with minimal loss of HPL activity. Activity by immunoassay and the production of lipolysis from isolated fat cells shows the material to be more potent than HPL prepared by previously described methods.