黑曲霉D2-26高温乳糖酶的酶学性质研究  

Studies on the Characterization of a Thermostable Lactase from Aspergillus niger D2-26

作　　者：李宁[1] 李红飞[2] 柯晓静[3] 于宏伟[1] 贾英民[1] 

机构地区：[1]河北农业大学食品科技学院,保定071001 [2]石药集团河北中润制药有限公司研究所,石家庄050041 [3]河北农业大学研究生处,保定071001

出　　处：《微生物学通报》2008年第7期1045-1050,共6页Microbiology China

基　　金：河北省农副产品加工重大科技专项课题资助项目(No.03220173D)

摘　　要：为研究黑曲霉来源的高温乳糖酶的酶学性质,对黑曲霉D2-26发酵液进行分离纯化使酶蛋白达到电泳纯,并对其进行酶学性质研究。结果表明:乳糖酶的最适温度70℃,在30℃～60℃有较高的耐受性;最适pH为2.5,pH稳定范围在2.0～9.0;Mn2+对乳糖酶活性有显著的激活作用,Hg2+、Pb2+对酶活有较强的抑制作用;SDS严重抑制了酶活性;以ONPG为底物采用双倒数做图法测得Vmax为97nmol/min,Km为8.77mmol/L;单亚基蛋白的分子量为116.978kD;糖基化程度为11.3%。The fermenting liquor from Aspergillus niger D2-26 was purified to obtain a single protein component, and then the characterization of thermostable lactase was studied. The enzyme had an optimum temperature of activity at 70℃ and an optimum pH of 2.5, and had good temperature tolerance from 30℃ to 60℃ and the pH stability at 2.0-9.0. Mn^2＋ had a significant activation on lactase activity, whereas the enzyme activity was inhibited strongly by Hg^2＋, Pb^2＋ and SDS; the Vmax, Km, molecular mass of single subunit protein and glycosylation of Lactase was 0.097 nmol/min, 8.77 mmol/L, 116.978 kD and 11.3%, respectively.

关 键 词：黑曲霉 乳糖酶 酶学性质 

分 类 号：Q93[生物学—微生物学]