脱毛碱性蛋白酶(DHAP)的饱和突变
Saturation mutagenesis of the dehairing alkaline protease

本实验在同源建模和氨基酸序列比对的基础上, 选取脱毛碱性蛋白酶（DHAP）8个氨基酸位点进行饱和突变. 通过牛奶平板和96孔板发酵筛选， 获得了4个催化特性改良的突变体, 测序鉴定为D248F, D248S, M233L和W214K. 利用酪蛋白和合成肽(AAPL ？？p？？N)作为底物, 对这些突变体进行了评价, 结果表明D248F、D248S、W214K在常温(28℃)下的酪蛋白水解活性提高; M233L在常温、高温(50℃)的酶活以及热稳定性都有增加. 同时, M233L和W214K在25℃和50℃水解AAPL ？？p？？N的酶活也分别得到了不同程度的提高.
From ？？Bacillus pumilus？？ BA06 an dehairing akaline protease（DHAP） has a good dehairing function and can be applied to relevant industries. On the basis of the homolog modeling and the multiple amino acids alignments, 8 amino acid residues of DHAP were selected for saturation mutagenesis. After screening on the skim milk plates and fermentation in the 96 well plates, 4 mutants were obtained and identified as D248F, D248S, M233L and W214K by DNA sequencing. The catalytic activities of D248F, D248S and W214K towards casein were improved at 28℃. And the caseinolytic activities of M233L were also improved at 50℃, 28℃, and after treatment at 65℃ for 10 minutes. The hydrolytic activities of M233L and W214K towards AAPL ？？p？？N were enhanced at 50℃ and 25℃