Ichikawa S, Nasrin S, Nagatsu T
Department of Biochemistry, Nagoya University School of Medicine, Japan.
Biochem Biophys Res Commun. 1991 Jul 31;178(2):664-71. doi: 10.1016/0006-291x(91)90159-5.
Enzymatically active mouse tyrosine hydroxylase (TH) was successfully expressed at a high level in Escherichia coli using a T7 RNA polymerase directed expression system. The specific activity of mouse TH in E. coli cell lysate was 7.5 nmol/mg protein/min. Kinetic characteristics of recombinant TH were examined. Km for tyrosine and (6R)-tetrahydrobiopterin (6R-BH4) cofactor were determined to be 7.2 microM (420 microM 6R-BH4), 19 microM [( 6R-BH4] less than 55 microM, 20 microM tyrosine) and 54 microM [( 6R-BH4] greater than 55 microM, 20 microM tyrosine), respectively. These were in good agreement with previously reported values for this enzyme.
使用T7 RNA聚合酶指导的表达系统，具有酶活性的小鼠酪氨酸羟化酶（TH）在大肠杆菌中成功实现了高水平表达。大肠杆菌细胞裂解物中小鼠TH的比活性为7.5 nmol/mg蛋白质/分钟。对重组TH的动力学特性进行了检测。酪氨酸和（6R）-四氢生物蝶呤（6R-BH4）辅因子的米氏常数分别确定为7.2 microM（420 microM 6R-BH4）、19 microM [（6R-BH4]小于55 microM，20 microM酪氨酸）和54 microM [（6R-BH4]大于55 microM，20 microM酪氨酸）。这些结果与该酶先前报道的值高度一致。
