来源于古细菌嗜酸热硫矿硫化叶菌(Sulfolobus acidocaldarius ATCC 33909)的麦芽寡糖基海藻糖水解酶(maltooligosyltrehalose trehalohydrolase，MTHase)是双酶法生产海藻糖的关键酶。对1株蛋白表达量提高1.9倍的突变株L202P/L218D/Y323G进行酶学性质方面的测定和海藻糖转化。对突变株L202P/L218D/Y323G SaMTHase进行最适温度、最适pH值、pH稳定性和60 ℃半衰期的测定，发现该突变株的酶学性质未发生较大变化。将麦芽四糖基海藻糖为底物，测定突变株L202P/L218D/Y323G SaMTHase酶动力学相关参数。将麦芽糊精(DE值5～7)作为底物，利用嗜酸热硫矿硫化叶菌的麦芽寡糖基海藻糖合成酶(maltooligosyl trehalose synthase，MTSase)与突变株L202P/L218D/Y323G SaMTHase以不同比例作用于底物生产海藻糖，海藻糖的转化率最高达到76.0%。

Maltooligosyltrehalose trehalohydrolase (MTHase), which is derived from the Sulfolobus acidocaldarius ATCC 33909, is a key enzyme in the couple enzymatic production of trehalose. The mutant strain L202P/L218D/Y323G, which has a 1.9-fold increase in protein expression, was used for the determination of enzymatic properties and trehalose conversion. The optimum temperature，optimum pH，pH stability and 60 ℃ half-life of mutant strain L202P/L218D/Y323G SaMTHase were determined. The results showed that there was no significant change in the enzymatic properties of the mutant strain. The kinetic parameters of the mutant strain L202P/L218D/Y323G SaMTHase were determined using maltotetraosyl trehalose as substrate. Using Maltodextrin (DE 5-7) as substrate, maltooligosyl trehalose synthase (MTSase) was mixed with the mutant L202P/L218D/Y323G SaMTHase at different ratios. The trehalose conversion results showed that trehalose conversion ratio was up to 76.0%.