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目的:对从栖热菌(Thermussp.A3)中分离得到的耐热乳糖酶进行纯化及部分理化性质的研究。方法:采用聚丙烯酰胺凝胶盘状电泳分离耐热乳糖酶,用5-溴-4-氯-3-吲哚-β-D半乳糖苷(x-gal)进行酶染显色,切下单一电泳带进行回收;分别用SDS-聚丙烯酰胺凝胶电泳法(SDS-PAGE)及非变性孔径梯度聚丙烯酰胺凝胶电泳法测定其分子质量,用聚丙烯酰胺管状等电聚焦电泳法测其等电点。结果表明:用SDS-PAGE法及梯度电泳法测定该耐热乳糖酶的分子质量分别为51.1kD和65.6kD;用等电聚焦电泳法测得其等电点约为7.2。结论:从栖热菌中提取的耐热乳糖酶的理化性质不同于其它来源的乳糖酶。
OBJECTIVE: To purify and study some physicochemical properties of heat-resistant lactase isolated from Thermus thermophilus (Thermussp.A3). Methods: Heat-resistant lactase was isolated by polyacrylamide gel electrophoresis and enzymatically stained with 5-bromo-4-chloro-3-indolyl-β-D galactoside A single electrophoresis zone was used for recovery. The molecular weights were determined by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and non-denaturing pore size gradient polyacrylamide gel electrophoresis. The polyacrylamide tubular isoelectric focusing electrophoresis Its isoelectric point. The results showed that the molecular mass of the thermostable lactase was 51.1kD and 65.6kD, respectively, as determined by SDS-PAGE and gradient electrophoresis. The isoelectric point was 7.2 by isoelectric focusing electrophoresis. CONCLUSION: The thermotolerant lactase extracted from Thermus bacteria is different in physicochemical properties from that of lactase from other sources.