Studies on Bovine Adrenal Ferredoxin

Summary

Native and reconstituted adrenal ferredoxins have been obtained in crystalline form. The apoprotein was prepared by treatment of the native protein with trichloroacetic acid. When the apoprotein was incubated with ferrous ion, sulfide and 2-mercaptoethanol, the recovery of the reconstituted protein was considerably low. The reconstitution was greatly enhanced by the presence of 8 M urea. The reconstituted protein was indistinguishable from the native protein with respect to enzymic activity, spectral properties and iron content. The apparent contents of labile sulfide in both native and reconstituted proteins were about one mole per mole of protein when analyzed according to the original methylene blue method without alkaline zinc incubation. Extension of the alkaline zinc incubation over 2 hr resulted in release of two moles of labile sulfide per mole of protein.