Purification of Corporin. 20

Abstract

The purification of corporin, the hormone of the corpus luteum responsible for progestational modification in the uterine mucosa, has been reported. 1 However, in recent work with this hormone we have purified the active material still further and have obtained a crystalline product which gives the characteristic physiological reaction when injected in female rabbits castrated in heat.

Method. The extraction and purification is carried out as previously described. 1 The 90% methyl alcohol solution containing the active material is evaporated and the solute taken up in 50% methyl alcohol (100 cc. per kg.) and extracted 3 times with an equal volume of low boiling petroleum ether. Only a small amount of activity is left in the 50% methyl alcohol solution, so it is discarded. The petroleum ether solution is evaporated and the solute is taken up in 15 cc. of 66% ethyl alcohol. This is chilled at 0°C. for 8-10 hours and the oily material is centrifuged off, redissolved in 66% alcohol and reprecipitated. After the second precipitation the supernatant fluids are united and evaporated to dryness and taken up in 5 cc. 50% ethyl alcohol. Any oily material which separates out is removed and discarded. Enough water is then added to make a 40% solution of alcohol and the solution is kept between 0°C. and —10°C. Crude crystalline material begins to separate out and is centrifuged off and recrystallized from 35-45% alcohol. After several crystallizations the resulting product consists, as far as can be determined microscopically, of colorless crystalline material.

The crystals are characteristically needlelike in shape if rapid crystallization has taken place.