Abstract
The moss Pogonatum inflexum contained proteins exhibiting SOD activity and comigration with a tracking dye in 7.5% native-PAGE. We purified the protein (SOD-like A) and characterized its molecular properties. SOD-like A indicated a subunit molecular mass of 15 kDa. In 13% native-PAGE, the cell extract of P. inflexum showed the presence of a minor SOD-like B with faster migration than SOD-like A. SOD-like A and B were sensitive to cyanide and H2O2, suggesting the presence of copper as a prosthetic metal. However, immunoblotting analysis indicated that both proteins differ with a typical chloroplastic or cytosolic CuZn-SOD. The molecular masses of SOD-like A and B were estimated by Furgason plot analysis to be 40 kDa and 10 kDa, respectively. Thus, SOD-like A is a homodimmer with somewhat higher molecular mass than those of typical plant CuZn-SODs of 32 kDa. Therefore, it is likely that P. inflexum contains novel types of SOD.
