期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1981
卷号：78
期号：11
页码：7052-7055
DOI：10.1073/pnas.78.11.7052
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Superoxide dismutase (SOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1 ) is known to be polymorphic in many organisms; in Drosophila, the degree of polymorphism has a wide range of variation from locality to locality within a given species. We have thoroughly purified from D. melanogaster the two common electromorphs, SODS and SODF. These differ in properties such as isoelectric point, specific activity, rate constant, thermostability, and amino acid composition. The specific activity is three times greater in SODS than in SODF, but the latter is more thermostable. In strains from California, SODS differs from SODF by at least one amino acid substitution: lysine in SODS is replaced by either aspartic acid or asparagine in SODF. This difference is consistent with the electrophoretic mobility and isoelectric points of the two electromorphs. In strains from Africa, SODS and SODF differ by two amino acid substitutions (histidine and proline in SODS vs. serine and either glutamic acid or glutamine in SODF) in addition to the one distinguishing the California strains. Thus the SODF electromorphs from California and from Tunisia, in spite of their identical electrophoretic mobility, differ by at least two amino acid substitutions.
