부산대학교 도서관

The properties of three types of adsorbents obtained by coupling oestradiol 7α-derivatives to agarose were compared. The adsorbents examined were: oestradiol 7α-decamethylene-agarose, oestradiol 7α-decamethylene-poly(alanyl-lysine)-agarose and oestradiol 7α-trimethylene-poly(alanyl- lysine)-agarose. The following results were obtained. (1) All these adsorbents are stable at 0 C for at least a year when stored in water. In the presence of cytosol they are stable for several hours and are reusable after a simple wash. (2) A new method allowing the calculation of the maximal receptor binding capacity of an absorbent was developed. (3) The geometry of the column and the dynamics of the loading have no influence on the binding capacity of the adsorbents. (4) Binding of the cytosol receptor to the adsorbent depends on whether the receptor had previously been partially purified by heparin-Ultrogel chromatography or treated with low or high salt concentration or trypsin. It was demonstrated that aggregation decreases the binding of the receptor to the adsorbents. (5) A satisfactory recovery of receptor upon elution is pos- sible only with biospecific adsorbents containing low concentrations of coupled steroid (≤ 0.2 mg/ml). The use of these adsorbents for the purification of the trypsin-treated receptor directly from cytosol allowed a 2500-fold purification corresponding to 5% pure protein (assuming one oestradiol binding site per molecule of Mr 60000). When starting from a low salt preparation containing the native 8-S receptor, partially purified by heparin-Ultrogel chromatography, preliminary experiments using affinity chromatography gave a further purification of 250-500-fold and led to a 50-90% pure protein (assuming one oestradiol binding site per molecule of Mr 70000). [ABSTRACT FROM AUTHOR]