PRESENCE OF AN ENDOGENOUS SUPEROXIDE-DISMUTASE ACTIVITY IN 3 RODENT MALARIA SPECIES

Superoxide dismutase (SOD) was investigated in three species of rodent malaria (Plasmodium berghei, P. yoelii and P. vinckei). The isoelectr ic points (pI) of isozymes found in purified parasites were identical. SOD activities detected by isoelectrofocusing at pl 5.0, 5.6, and 6.4 were cyanide-sensitive and could be considered as having been adopted by the parasites from the host red blood cell. The three rodent malar ia parasites also contained a cyanide-resistant, hydrogen peroxide-sen sitive SOD activity not found in the host red blood cell. It is theref ore concluded that the three rodent malaria parasites possess an endog enous SOD. Two bands of endogenous SOD were found at pl 6.2 and 6.8 fo r the three species, and one additional band was detected at pl 5.7 fo r P. berghei and P. vinckei. This first report in rodent Plasmodium of a cyanide-resistant, hydrogen peroxide-sensitive SOD suggests that th ese parasites may be capable of at least partly resisting activated ox ygen species using an endogenous SOD.