Rechsteiner T, Leisinger T
Mikrobiologisches Institut, Eidgenössische Technische Hochschule, ETH-Zentrum, Zürich, Switzerland.
Eur J Biochem. 1989 Apr 15;181(1):41-6. doi: 10.1111/j.1432-1033.1989.tb14691.x.
The isoleucyl-tRNA synthetase of the archaebacterium Methanobacterium thermoautotrophicum was purified 1500-fold to electrophoretic homogeneity by a procedure based on affinity chromatography on Sepharose-bound pseudomonic acid, a strong competitive inhibitor of this enzyme. The purified enzyme is a monomer with a molecular mass of 120 kDa. In this respect and in its Km values for the PPi-ATP exchange, and aminoacylation reactions, it resembles the isoleucyl-tRNA synthetases from eubacterial and eukaryotic sources. Its aminoacylation activity is optimal at pH 8.0 and at 55 degrees C. Pseudomonic acid is a strong competitive inhibitor of the aminoacylation reaction with respect to both L-isoleucine (KiIle 10 nM) and ATP (KiATP 20 nM).
嗜热自养甲烷杆菌的异亮氨酰 - tRNA合成酶通过基于琼脂糖结合的假单胞菌酸（该酶的一种强竞争性抑制剂）的亲和色谱法纯化了1500倍，达到电泳纯。纯化后的酶是一种分子量为120 kDa的单体。在这方面以及在其对PPi - ATP交换和氨酰化反应的Km值方面，它类似于来自真细菌和真核生物来源的异亮氨酰 - tRNA合成酶。其氨酰化活性在pH 8.0和55℃时最佳。假单胞菌酸是氨酰化反应中L - 异亮氨酸（KiIle 10 nM）和ATP（KiATP 20 nM）的强竞争性抑制剂。
