Determination of recombinant Cu/ZnSOD protein expressed by P. pastoris SMD1168H. Concentrated supernatant samples (6-fold) of the yeast culture incubated for 96 hours at 28.5°C were analyzed by 15% SDS-PAGE staining (left). Immunoblots were immunodecorated with Cu/ZnSOD specific antisera (right). Mw, molecular weight marker (Fermentas); pGAPZαA-SOD, supernatant of SMD1168H-pGAPZαA-SOD; pGAPZαA, supernatant of SMD1168H transformed with the empty vector (background expression). The arrows indicate bands of the secreted recombinant SOD protein.