| Abstract: | The EE and SS isozymes of horse liver alcohol dehydrogenase have been immobilized separately to weakly CNBr-activated Sepharose 4B. The resulting immobilized dimeric preparations lost practically all of their activity after treatment with 6 M urea. However, enzyme activity was regenerated by allowing the urea-treated Sepharose-bound alcohol dehydrogenase to interact specifically with either soluble subunits of dissociated horse liver alcohol dehydrogenase or soluble dimeric enzyme. The regeneration of steroid activity in the immobilized preparations after treatment of the bound S subunits with soluble E subunits seems to show that true reassociation of the enzyme had taken place on the solid phase, since only isozymes with an S-polypeptide chain are active when using 5 beta-dihydrotestosterone as substrate. The results presented in this paper indicate that immobilized single subunits of horse liver alcohol dehydrogenase are inactive and that dimer formation is a prerequisite for the enzymic activity. |
