Selective tryptophan determination using tryptophan oxidases involved in bis-indole antibiotic biosynthesis.

摘要: A novel tryptophan assay was developed using oxidases. Although many l-amino acid oxidases (LAAOs) have been reported to catalyze oxidation, most of them broad substrate specificity and oxidize multiple amino acids besides tryptophan. To obtain a tryptophan-specific LAAO, we focused on bis-indole antibiotic biosynthesis, bacterial secondary metabolic pathway. putative LAAO from Streptomyces sp. TP-A0274, StaO involved in staurosporine heterologously expressed, biochemically characterized, shown serve as selective oxidase for the first time. In addition, another VioA violacein biosynthesis Chromobacterium violaceum, characterized comparison with StaO. Interestingly, share similar properties, namely narrow high affinity l-tryptophan, despite phylogenetic distance between these enzymes. Owing features, uncommon among known LAAOs, assays can be used accurate quantification l-tryptophan via coupled colorimetric reaction. Indeed, provided concentrations human plasma accurately those obtained by high-performance liquid chromatography. Therefore, enzymes were clearly offer an effective method determining biological samples rapidly, inexpensively, accurately. The results here also suggest possibility metabolism-oriented screening strategy highly individual biomolecules.