BMB Reports
- 제33권1호
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- Pages.82-88
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- 2000
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- 1976-670X(eISSN)
Molecular Cloning of an Extremely Thermostable Alanine Racemase from Aquifex pyrophilus and Enzymatic Characterization of the Expressed Protein
- Kim, Sang-Suk (Structural Biology Center, Korea Institute of Science and Technology) ;
- Yu, Yeon-Gyu (Structural Biology Center, Korea Institute of Science and Technology)
- 투고 : 1999.10.04
- 심사 : 1999.11.11
- 발행 : 2000.01.31
초록
A homologous gene to alanine racemase was cloned from a hyperthermophilic bacterium, Aquifex pyrophilus. The cloned gene encodes a protein of 341 amino acids, which has a significant homology to alanine racemase of Bacillus stearothermophilus, Lactobacillus brevis, and E. coli. When the gene was expressed in Escherichia coli, it produced a 40 kDa protein. The purified protein contains one mole pyridoxal 5-phosphate per one mole of protein, which is essential for catalytic activity of alanine racemase. The purified protein catalyzed racemization of L-alanine to D-alanine, or vice versa, indicating that the cloned gene encoded alanine racemase. It also showed significant racemization activity against L-serine and