title: A superoxide dismutase of metacestodes of Taenia taeniaeformis.
abstract: Superoxide dismutase was purified from Taenia taeniaeformis metacestodes by sequential ion exchange chromatography on quaternary-amino-ethyl-cellulose, gel filtration chromatography on ACA 44 and ion exchange chromatography on DEAE-cellulose, followed by chromatofocusing on polybuffer exchanger 94. This isolation procedure resulted in the detection of a single protein-staining band on alkaline gels, coincident with enzyme activity. We have, however, detected what appear to be two peaks of enzyme activity within this single protein-staining band. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis using gradient slab gels and analysis under reducing conditions, resulted in the detection of only one protein at an apparent Mr of 16,600, while analysis under non-reducing conditions, gave a single protein of an apparent Mr of 64,000. The isoelectric point of the purified protein is 6.6. Boiling for 3 min completely destroyed the enzyme, whereas incubation for 2 h at 37 degrees C resulted in the loss of 56% of the enzymic activity. Incubation with 10 mM KCN resulted in 83% inhibition of the enzyme. We have detected up to 168 U ml-1 of enzyme activity in the cyst fluid surrounding the parasite in situ. This is the first instance in which any parasite superoxide dismutase has been purified to apparent homogeneity. Parasite-mediated enzymic destruction of superoxide anion can not only protect against oxygen toxicity as a result of normal parasite respiratory processes but also may serve as yet another mechanism used by tissue-dwelling parasites to evade host immunologic attack.
mesh_terms: D000818:Animals; D002845:Chromatography; D004586:Electrophoresis; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D011190:Potassium Cyanide / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D013621:Taenia / Q000201:enzymology* / Q000254:growth & development
chemical_list: D013482:Superoxide Dismutase; D011190:Potassium Cyanide