Isolation of Manganese-Containing Superoxide Dismutases

Manganese-containing superoxide dismutases (MnSOD) have been purified from diverse sources, including aerobic bacteria, ^{1 , 2} yeast, ³ rat and bovine liver mitochondria, ^{4 , 5} and pea leaves. ⁶ A detailed scheme for purification of MnSOD from Bacteroides thetaiotaomicron, a Gram-negative nonspore-forming anaerobe common to the gut of man and other animals, is presented here. These bacteria actually synthesize an FeSOD during their anaerobic growth, but they produce a MnSOD upon aeration of the culture. ⁷ The purification of B. thetaiotaomicron MnSOD demonstrates the logic used in purifying an enzyme from a crude cell extract, but the sequence presented here cannot be assumed to be valid for purification of every MnSOD. A brief reveiw of procedures different from those used with B. thetaiotaomicron MnSOD is therefore also included.