[Purification of the human prostate androgen receptor. III. Purification of the androgen receptor and characterization of the purified androgen receptor].

With 855 g of benign prostatic hypertrophic tissue as starting material, the androgen receptor (AR) was purified by combining the affinity chromatography of heparin Sepharose CL-6B and of R1881-carboxymethyloxime-albumin Sepharose 4B. The final purificationfraction had high-affinity, low-capacity binding to 3H-R1881 in the presence of 1,000-fold molar excess of triamicinolone acetonide (TA) with a dissociation constant of 2.4 nM. When the relative binding affinity was being assessed, the binding of the final purification fraction to 3H-R 1881 was not suppressed by estradiol or TA and revealed the binding specificity of the AR. Polyacrylamide gel electrophoresis showed no albumin or TeBG mixed in the final purification fraction. These results give evidence that the AR had been purified and that, in comparison with the original cytosol, the degree of purification was approximately 2,360 fold. The molecular weight of the purified AR was 32,000 as calculated by high performance liquid chromatography. The fact the antiserum from rabbit immunized with the purified AR showed a reaction against the purified AR leads us to believe that antibodies for the AR were successfully produced. Further immunological study on AR measurement is considered to be of great importance.