中文摘要：

将来自腾冲菌的脂肪酶（LipA）基因（lipA）克隆到大肠杆菌表达载体pET28a（含T7启动子）和pTrc99A （含Trc启动子）中，转入大肠杆菌表达，发现Trc启动子更适合LipA的表达。通过热处理和DEAE-Sepharose阴离子柱纯化过程，重组LipA得到纯化，比酶活达到1.9U/mg，重组LipA分子量为42kDa。重组LipA在80℃、pH 4.5时酶活最高，经85℃保温2h，酶活保持60%以上；在pH值4.0～6.0之间，LipA具有较好的稳定性；Cu^2＋和Zn^2＋对酶活力分别有38.9%和69.2%的抑制作用，Mn^2＋、Co^2＋和Tween-20对该酶有较大的激活作用；以p-nitrophenyl-laurate （p-NP-C12）为底物时，该酶的Km值为1.5mmol/L，kcat为34.5s-1。

英文摘要：

The lipase from Thermoanaerobacter tengcongensis （LipA） is a kind of ester-bond hydrolysis enzyme catalyst of triacylglycerol. The LipA genes （lipA） were cloned into pET28a （T7 promoter） and pTrc99A （Trc promoter）,yielding pET28a-lipA and pTrc99A-lipA,and transformed into the Escherichia coli BL21 （DE3） and Top10 , respectively. The strain harboring pTrc99A-lipA produced more recombinant LipA than the strain harboring pET28a-lipA. The recombinant LipA was purified to homogeneity from E. coli by a simple two-step procedure involving heat treatment and DEAE-Sephacel. The purified recombinant LipA reached 1.9U/mg. The recombinant LipA had a molecular mass of 42kDa on SDS-PAGE. The maximum activity was at pH 4.5 and 80℃. The purified enzyme was stable from pH 4.0—6.0,and retained approx. 60%of its activity after 2h at 85℃. The LipA activity were decreased 38.9%and 69.2%by Cu^2＋and Zn^2＋（5mmol/L）,respectively. Mn^2＋,Co^2＋and Tween-20 had positive effect on the activity of LipA. The recombinant LipA had a Km of 1.5 mmol/L and kcat of 34.5s-1 for p-nitrophenyl-laurate.