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从烟叶中提取的超氧物歧化酶（ＳＯＤ），经ＰＡＧＥ垂直板电泳后，用氮蓝四唑（ＮＢＴ）法活性染色，并经凝胶薄层扫描（λ＝５９５ｎｍ），结果显示粗酶液有６条同工酶谱带，经纯化后的酶只有一条谱带。此纯酶液置冰箱３６ｈ后，可获得长方形结晶。结晶酶液用ＳｅｐｈａｄｅｘＧ－１００柱层析（１．５ｃｍ×１００ｃｍ）和ＳＤＳ－和ＳＤＳ－ＰＡＧＥ测得其分子量分别为２４８３０和２８９００。用等电聚焦电泳测得该酶等电点为６．８０。该酶在ｐＨ５～９范围内活性较稳定，在７５℃保温１５ｍｉｎ活性尚保留５４％。此酶对ＫＣＮ、氯仿－乙醇不敏感，但受到ＥＤＴＡ，Ｈ_２Ｏ_２的强烈抑制，表明烟叶中分离纯化得到的ＳＯＤ为酶分子中结合Ｆｅ的Ｆｅ－ＳＯＤ。
Superoxide dismutase (SOD) extracted from tobacco leaves was electrophoresed by PAGE vertical plate and then stained with NBT method and scanned by TLC (λ = 595nm). The results showed that crude enzyme The liquid has 6 isozyme bands, the purified enzyme has only one band. The pure enzyme solution placed in the refrigerator 36h, to obtain a rectangular crystal. The molecular weight of the crystallization enzyme solution was 24830 and 28900 respectively by SephadexG-100 column chromatography (1.5cm × 100cm) and SDS- and SDS-PAGE. The isoelectric point of this enzyme was 6.80 measured by isoelectric focusing electrophoresis. The activity of the enzyme in the pH5 ~ 9 range of more stable activity at 75 ℃ for 15min retained 54% activity. The enzyme was not sensitive to KCN and chloroform-ethanol, but strongly inhibited by EDTA and H_2O_2. It showed that the SOD isolated and purified from tobacco leaves was Fe-SOD which bound Fe in the enzyme molecule.