Characterization of manganese superoxide dismutase from Flammulina velutipes

From the paper

Abstract

Superoxide dismutase (SOD) activities in different parts of the fruiting body at different stages of Flammulina velutipes were analyzed. MnSOD was found to be the major form. MnSOD activity of F. velutipes varies depending upon collection sites, growth, and the various parts of the fruiting body examined. The molecular mass of the monomer of MnSOD present in F. velutipes was estimated to be about 20 kDa by SDS-PAGE. The functional forms consists of a tetramer and a form with a larger molecular size. pIs of the MnSODs in F. velutipes were located at pH 4.8, 5.0 and 5.3 by isoelectric focusing. The SOD activity of F. velutipes was heat-labile. Although more than 50% of the MnSOD activity was retained after incubated at 40 or 50 degrees C for 20 min, no activity was detected after 70 degrees C treatment for 20 min. The SOD activity was not detected at a pH less than 4.0, however, it was pH-independent in the range of pH 5-9.