A thermostable L-aspartate oxidase from Sulfolobus tokodaii: characterization and biotechnological applications

L-Amino acid oxidases (LAAOs) are FAD-containing enzymes catalyzing the stereospeci???c oxidative deamination of L-amino acids to ??-keto acids, ammonia and hydrogen peroxide. LAAOs have not been widely employed yet in biotechnological applications because of the dif???culties in their expression as recombinant proteins in prokaryotic hosts. As a suitable altemative, in this work, L-aspartate oxidase from the thermophilic archea Sulfolobus tokodaii, (StLASPO, active on L-aspartate and L-asparagine only) has been efficiently produced as recombinant protein in E. coli in the active form as holoenzyme and fully characterized [1]. StLASPO is fully stable up to 80 °C, possesses maximal activity at 75-80 °C and is stable in a broad range of pH (7.0???10.0). Moreover, it shows only a weak inhibition from the product oxaloacetate and by D-aspartate and a tight cofactor binding. All these features make StLASPO an attractive enzyme for many biotechnological applications. Accordingly, StLASPO has been ef???ciently employed in the kinetic resolution of racemic mixture of D,L-aspartate (e.e. > 99%) and, recently, it has been immobilized on different solid supports in order to facilitate the enzyme reusability. References 1 Bifulco D. et al. (2013), A thermostable L-aspartate oxidase: a new tool for biotechnological applications, Appl Microbiol Biotechnol, 97:7285???7295.