谷氨酰胺转胺酶的分离纯化及酶学性质研究

Study on Purification and Characterization of Microbial Transglutaminase

采用离子交换层析和凝胶过滤层析等方法,分离纯化获得了轮枝链霉菌(Streptoverticillium SK4.001)谷氨酰胺转胺酶。同时研究了该酶的酶学性质及反应动力学参数,结果表明,该酶最适反应温度和pH分别为50℃和7.0,温度稳定范围为20-40℃,pH稳定范围为5.6-7.0;Na+,K+,Ca2+,Mg2+,Ba2+不会抑制酶的活性,Zn2+,Fe3+,Cu2+,Pb2+会强烈抑制酶的活性,Mn2+会部分抑制酶的活性,酶的活性部位没有金属离子的参与。以CBZ-Gln-Gly为底物,该酶的Km值为15.81mmol/L,Vmax为16.69μmol/(mL·min)。

Transglutaminase （TGase） is a kind of thiol enzyme that catalyzes acryl-transfer reaction, which introduces inter- or intra-molecular covalent crosslinks in many proteins, changing the quality of food products. Transglutaminase from Streptoverticillium SK4. 001 was purified by ion-exchange chromatography and gel filtration chromatography. The purified transglutaminase exhibited optimum activity at 50℃ and pH7.0. It was stable below 40℃ and within a pH range of 5.6-7.0. The enzyme was not inhibited byNa ^＋ K^＋, Ca^2＋, Mg^2＋, Ba^2＋, but it was stronglyinactivated by Zn^2＋ , Fe^3＋ , Cu^2＋ , Pb^2＋ and was partly inhibited by Mn^2＋,suggesting that this enzyme could not possess a metal ion at the active site. The purified enzyme presented a Km of 15.81 mmol/L and a Vmax of 16. 69μmol/ （mL· min） for CBZ-Gln-Gly.