Isolation and characterization of thermostable D-amino acid oxidase

D-氨基酸氧化酶(DAO)是一种重要的生物技术酶，可用于D-氨基酸的测定和医药中间体的生产等。在本研究中，我们在嗜热菌中鉴定了一个DAO同源基因(RxDAO)，并表明在大肠杆菌中产生的基因产物比已知的DAOS具有更高的稳定性。此外，我们在另一种嗜热菌和一种嗜热真菌中鉴定了DAO同源基因，表明可能存在其他高度稳定的DAO。综上所述，我们成功地确定了一种新型的、高度稳定的DAO，可用于各种工业领域的实际应用。

D-Amino acid oxidase (DAO) is a biotechnologically important enzyme that can be used for various applications, such as the determination of D-amino acids and the production of pharmaceutical intermediates. Therefore, a highly stable DAO has been desired.In this study, we identified a DAO homologous gene (RxDAO) in the thermophilic bacterium Rubrobacter xylanophilus, and showed that the gene product produced in E. coli has a much higher stability than known DAOs. In addition, we identified DAO homologous genes in another thermophilic bacterium and also in a thermophilic fungus, showing the possibility of the additional existence of other highly stable DAOs. In conclusion, we successfully identified a novel, highly stable DAO useful for practical applications in various industrial fields.