Relations between conformations and activities of lipoamide dehydrogenase: III. Protein association—dissociation and the influence on catalytic properties

摘要: Abstract 1. The molecular weights of lipoamide dehydrogenase holoenzyme and its Cu2+-modified form have been determined by gel filtration ultracentrifugation to be twice those the apoenzyme DCIP-active enzyme obtained binding FAD at 0–5°, i.e., 104 000 52 000, respectively. 2. Upon anaerobic reduction with excess NADH in 8 M urea, a protein could isolated that was able reconstitute activity oxidized lipoate. 3. upon freezing shows, under present conditions, original weight, while NADH, is formed which monomer. 4. Association—dissociation phenomena are involved reversible conversion lipoate into DCIP activity. evidence association—dissociation occurs will discussed connection proposed models for structure this enzyme.