酵母表达芥子酶基因TGG4、TGG5的酶学特性差异研究

十字花科植物广泛存在芥子酶,并利用芥子酶以抵御病虫害的侵袭。TGG4和TGG5是在拟南芥中发现的新型芥子酶基因,二者基因序列极为相近。本试验通过对转TGG4和TGG5基因酵母的诱导表达及相应重组蛋白的纯化,探讨两个蛋白的酶学差异性。结果表明:TGG4、TGG5的最大Vc激发浓度都为1mmol/L;但是在最适反应温度和最适反应pH上,两个重组蛋白略有不同,TGG4和TGG5的最适温度分别为67℃和57℃,而最适pH分别为6.5和5.5,TGG4比TGG5要耐高温耐碱性;这两个重组蛋白酶活性都受NaCl的抑制。

The Study of Properties Differences in TGG4 and TGG5 Yeast Recombinant Protein

Glucosinolate-myrosinase is commonly found in cruciferous plants used to help plants resist the inva-sion of pests and diseases.TGG4 and TGG5 are two new myrosinase genes discovered in Arabidopsis with similar DNA sequence.In this study,we identified the TGG4 and TGG5 transgenic yeast,then we induced and purified the recombinant proteins.Finally,we discussed the properties differences between these two enzymes.The results showed that the biggest Vc stimulating concentration of the both enzymes is 1 mmol/L,but the optimum reaction temperatures and the optimum pH’s of the two recombinant proteins are a little different: the optimum temperature are 67℃ and 57℃ respectively,and the optimal pH are 6.5 and 5.5,respectively.TGG4 seemsto bemore tempera-ture resistant and alkali resistance.Both two restructuring proteins’ activities were suppressed by NaCl.