A new affinity resin for purification of non-transformed avian progesterone receptor.

A new steroid affinity resin has been developed which can be successfully used to partially purify the non-transformed species of the progesterone receptor from chick oviduct. Deoxycorticosterone has been modified through its 21-carbon and linked to a stable spacer arm which is attached to Sepharose 2B by an epoxide technique. The affinity resin is very resistant to chemical breakdown or to enzymatic destruction in crude tissue extracts. We have standardized the capacity and optimum conditions for elution of receptor which is bound to the affinity resin. Receptor purification of several hundred-fold can be obtained routinely with good yield. The cytosol receptor prepared in the presence of sodium molybdate remains in the non-transformed 8S state following affinity chromatography.