[Human manganese-containing superoxide dismutase: enzyme immunoassay and contents in lung cancer].
A manganese-containing superoxide dismutase (Mn-SOD) was isolated from human liver mitochondria by the procedures including heat treatment, ammonium sulfate precipitation, ion exchange chromatography, gel filtration and isoelectric focusing. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the purified enzyme showed a single band with an approximate molecular weight of 20,000. Judging from the molecular weight of an approximate 80,000 estimated by gel filtration and the above electrophoretic result, the native Mn-SOD exists as a tetramar. Ouchterlony test using a monospecific goat antiserum against the purified liver Mn-SOD indicated that the enzymes from normal lung as well as lung cancer were immunochemically identical. A solid phase enzyme immunoassay (EIA) was established to detect this Mn-SOD enzyme protein in the tissue homogenates. The working range by this assay was from 10 ng to 1,000 ng. The enzymatic activities and the immunological contents of the Mn-SOD in human lung carcinoma and uninvolved lung were compared. The enzyme contents determined by EIA were significantly elevated in carcinoma tissues as compared to the normal uninvolved tissues (37.4 micrograms/mg protein and 17.9 micrograms/mg protein, respectively). However no significant difference was seen in the enzyme activities. Among histological types of lung carcinoma, adenocarcinoma had a significantly high Mn-SOD content. These results suggest that the carcinoma tissues contain an immunologically active, but enzymatically inactive form of Mn-SOD enzyme.
D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007124:Immunoenzyme Techniques; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008175:Lung Neoplasms / Q000201:enzymology*; D008345:Manganese / Q000032:analysis*; D013482:Superoxide Dismutase / Q000032:analysis*
D007106:Immune Sera; D008345:Manganese; D013482:Superoxide Dismutase