伤寒沙门氏菌SOD的提取及抗原性研究

经硫酸铵分级沉淀，ＤＥＡＥ纤维素柱层析提取了伤寒沙门氏菌ＳＯＤ。提取后酶的比活性为３２７０Ｕ／ｍｇ，经聚丙烯酰胺凝胶电泳，蛋白质染色及酶活性染色显示提取的ＳＯＤ达到了电泳纯。酶活性染色法和原子吸收分光光度法测定结果表明提取的ＳＯＤ为Ｆｅ－ＳＯＤ。双向琼脂扩散试验结果显示抗伤寒沙门氏菌Ｆｅ－ＳＯＤ血清与牛红细胞ＳＯＤ不形成沉淀线，提示伤寒沙门氏菌Ｆｅ－ＳＯＤ与牛红细胞ＳＯＤ无交叉反应，抗体对酶活性抑制试验结果显示抗Ｆｅ－ＳＯＤ血清可抑制伤寒沙门氏菌及鼠伤寒沙门氏菌的Ｆｅ－ＳＯＤ和Ｆｅ／Ｍｎ－ＳＯＤ活性，对Ｍｎ－ＳＯＤ活性无抑制作用，说明伤寒沙门氏菌和鼠伤寒沙门氏菌的ＳＯＤ之间有共同抗原，也提示ＳＯＤ的辅基似乎决定了其抗原特异性。

Purification and Antigenicity Analysis of Superoxide Dismutase from Salmonella typhi

The superoxide dismutase in a wild strain of Salmonella typhi was purified through cell destruction by ultrasonic wave first and followed by DEAE-cellulose chromatography. The results showed that the specific activity of the purified SOD was 3270 U/mg protein. The purified SOD was mainely Fe-SOD as determined by enzyme activity inhibrtion test and atomic absorption spectrophotometry. After PAGE the purified SOD was stained by Coomassie blue and the inhibition reaction was identified by nitro blue tetrazolium reduction. The results indicated ihat the FeSOD preparation was of higher purity. The anti-S. lyphi Fe-SOD antiserium was raised in rabbit with the purified S. typhi Fe-SOD. The titer of the antiserium was 1:10 240 assayed by ELISA.The results of immunoeletrophoresis showed that the cell-free extracts and purified SOD of S. typhi formed one precipitated line with the antiserum in the same area, separately. The results of the double diffusion test indicated that the SOD from bovine erythrocyte did not cross react with the Fe-SOD from S.typhi,the antiserum could inhibit the activity of both the Fe-SOD and Fe/MnSOD, but not Mn-SOD within the purified Fe-SOD and cell-free extracts of the S. typhi assayed by PAGE.