Enantiomerically pure α‐amino acids are compounds of primary interest for the fine chemical, pharmaceutical, and agrochemical sectors. Amino acid oxidases are used for resolving d,l‐amino acids in biocatalysis. We recently demonstrated that l‐amino acid deaminase from Proteus myxofaciens (PmaLAAD) shows peculiar features for biotechnological applications, such as a high production level as soluble protein in Escherichia coli and a stable binding with the flavin cofactor. Since l‐amino acid deaminases are membrane‐bound enzymes, previous applications were mainly based on the use of cell‐based methods. Now, taking advantage of the broad substrate specificity of PmaLAAD, a number of natural and synthetic l‐amino acids were fully converted by the purified enzyme into the corresponding α‐keto acids: the fastest conversion was obtained for 4‐nitrophenylalanine. Analogously, starting from racemic solutions, the full resolution (ee >99%) was also achieved. Notably, d,l‐1‐naphthylalanine was resolved either into the d‐ or the l‐enantiomer by using PmaLAAD or the d‐amino acid oxidase variant having a glycine at position 213, respectively, and was fully deracemized when the two enzymes were used jointly. Moreover, the complete stereoinversion of l‐4‐nitrophenylalanine was achieved using PmaLAAD and a small molar excess of borane tert‐butylamine complex. Taken together, recombinant PmaLAAD represents an l‐specific amino acid deaminase suitable for producing the pure enantiomers of several natural and synthetic amino acids or the corresponding keto acids, compounds of biotechnological or pharmaceutical relevance.

中文翻译：

---

l-氨基酸脱氨酶对α-氨基酸的脱硫和立体转化

对映体纯的α-氨基酸是精细化工，制药和农用化学领域的主要关注化合物。氨基酸氧化酶用于解析生物催化中的d，l-氨基酸。我们最近证明升-氨基从酸脱氨酶变形杆菌myxofaciens（PmaLAAD）所示特有的特征在于用于生物技术应用中，诸如高生产水平作为可溶性蛋白的大肠杆菌和稳定的与黄素辅因子结合。由于l-氨基酸脱氨酶是膜结合酶，因此以前的应用主要基于基于细胞的方法。现在，利用PmaLAAD广泛的底物特异性，可以使用多种天然和合成的纯化的酶将l-氨基酸完全转化为相应的α-酮酸：4-硝基苯丙氨酸转化最快。类似地，从外消旋溶液开始，也实现了全分辨率（ee > 99％）。值得注意的是，分别使用PmaLAAD或在213位具有甘氨酸的d-氨基酸氧化酶变体将d，l -1-萘丙氨酸解析为d-或l-对映异构体，并在将这两种酶分离后完全脱脂。共同使用。此外，完整的stereoinversion升使用PmaLAAD和小摩尔过量的甲硼烷的达到-4-硝基苯丙氨酸叔-丁胺复合物。综上所述，重组PmaLAAD代表一种l特异性氨基酸脱氨酶，适用于生产几种天然和合成氨基酸或相应的酮酸，生物技术或药物相关化合物的纯对映体。