Mizobata T, Fujioka T, Yamasaki F, Hidaka M, Nagai J, Kawata Y
Faculty of Engineering, Tottori University, Tottori, 680-8552, Japan.
Arch Biochem Biophys. 1998 Jul 1;355(1):49-55. doi: 10.1006/abbi.1998.0693.
A thermostable fumarase was purified from a strain of Thermus thermophilus isolated from a Japanese hot spring. The maximum specific activity of the purified enzyme was 1740 units/mg at pH 8.0 and 85 degreesC. The enzyme was composed of four identical subunits with a molecular weight of 46,000 and displayed other enzymatic characteristics which are common to the class II fumarases. The thermal stability of the purified enzyme was remarkable, with over 80% of the activity remaining after a 24-h incubation at 90 degreesC. The enzyme was also resistant to chemical denaturants; 50% of the initial specific activity was detected in assay mixtures containing 0.8 M guanidine hydrochloride. The purified enzyme shared an extremely high sequence homology with Thermus aquaticus fumarase and Bacillus subtilis fumarase in the first 43 amino acid residues.
从一株分离自日本温泉的嗜热栖热菌中纯化出一种耐热富马酸酶。纯化后的酶在pH 8.0和85℃时的最大比活性为1740单位/毫克。该酶由四个分子量为46000的相同亚基组成，并表现出II类富马酸酶共有的其他酶学特性。纯化后的酶热稳定性显著，在90℃孵育24小时后仍保留超过80%的活性。该酶还对化学变性剂具有抗性；在含有0.8 M盐酸胍的测定混合物中检测到初始比活性的50%。纯化后的酶在前43个氨基酸残基上与嗜热水栖热菌富马酸酶和枯草芽孢杆菌富马酸酶具有极高的序列同源性。
