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首页> 外文期刊>Infection and immunity >Isolation and properties of levanase from Streptococcus salivarius KTA-19.
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Isolation and properties of levanase from Streptococcus salivarius KTA-19.

机译：唾液链球菌KTA-19的Levanase的分离和性质。

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Fructan-hydrolyzing enzyme from Streptococcus salivarius KTA-19 isolated from human dental plaque was investigated. The enzyme was purified by ammonium sulfate precipitation, acetone fractionation, and column chromatography on Bio-Gel and DEAE-cellulose. The purified enzyme showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing. Its molecular weight was 100,000 as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme exhibited an optimum pH of 6.5 and decreased its activity from pH 6.0 and especially below pH 5.5. The optimum temperature was 40 to 50 degrees C, and enzyme activity was reduced by 90% at 55 degrees C. Enzyme activity was markedly inhibited by Hg2+, Ag+, Cu2+, and p-chloromercuribenzoate at a concentration of 10(-3) M, but not by other metal ions or chemical effectors. Fructose was the only by-product of the enzyme action on levan. These results indicated that the levanase of S. salivarius KTA-19 is an exo-beta-(2,6)-fructofuranosidase.
机译：研究了从人牙菌斑中分离的唾液链球菌KTA-19的果聚糖水解酶。通过硫酸铵沉淀，丙酮分级分离以及在Bio-Gel和DEAE-纤维素上的柱色谱法纯化酶。纯化的酶在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和等电聚焦上显示单一条带。通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳测定，其分子量为100,000。该酶表现出最佳pH值为6.5，并且从pH 6.0降低活性，尤其是在pH 5.5以下。最佳温度为40到50摄氏度，并且在55摄氏度时酶活性降低了90％。Hg2+，Ag +，Cu2 +和对氯汞苯甲酸在10（-3）M的浓度下显着抑制了酶的活性，但不能通过其他金属离子或化学效应器。果糖是酶作用于莱文的唯一副产物。这些结果表明唾液链球菌KTA-19的levanase是exo-β-（2,6）-果糖呋喃糖苷酶。

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