Purification, Characterization and Gene Cloning of Thermostable Ο-Acetyl-L-Homoserine Sulfhydrylase Forming γ-Cyano-α-Aminobutyric Acid (ENZYMOLOGY, PROTEIN ENGINEERING, AND ENZYME TECHNOLOGY)

概要

論文の詳細を見る
A thermophilic and cyanide ion-tolerant bacterium, Bacillus stearothermophilus CN3 isolated from a hot spring in Japan, was found to produce thermostable γ-cyano-α-aminobutyric acid synthase. The enzyme was purified and characterized. The purified and characterized. The purified enzyme has a molecular mass of approximately 180 kDa and consists of four identical subunits. It was stable in the pH range of 6.0 to 10.5 and up to 60℃. The enzyme catalyzed the γ-replacement reaction of Ο-acetyl-L-homoserine with cyanide ions. The gene encoding the γ-cyano-α-aminobutyric acid synthase was isolated from B. stearothermophilus CN3. Sequence homology analysis revealed that the γ-cyano-α-aminobutyric acid synthase from the bacterium is Ο-acetyl-L-homoserine sulfhydrylase. A recombinant plasmid, constructed by ligation of the cloned gene and an expression vector, was introduced into Escherichia coli JM109. The transformed E. coli cells overexpressed γ-cyano-α-aminobutyric acid synthase. The heat stable γ-cyano-α-aminobutyric acid synthase can be applied to the synthesis of [5-^<11>C] L-glutamic acid used as a tracer for positron emission tomography.
社団法人日本生物工学会の論文
2003-07-25