The Purification and Properties of Superoxide Dismutase from Neurospora crassa

Abstract Soluble extracts of Neurospora crassa contain a single, electrophoretically distinct, superoxide dismutase. This enzyme has been isolated and has been found to be a blue-green, copper- and zinc-containing enzyme, similar to that already described from bovine tissues and from garden peas. The molecular weight was approximately 31,000, and the enzyme appeared to be composed of 2 subunits of equal size joined only by noncovalent interractions. The Neurospora enzyme contains two Cu++ and two Zn++ per molecule. The ultraviolet absorption spectrum indicates a lack of tryptophan. Amino acid analyses are reported as are the spectral and catalytic properties.