Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Jülich, Germany.
Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Jülich, Germany.
FEBS Open Bio. 2023 Dec;13(12):2224-2238. doi: 10.1002/2211-5463.13723. Epub 2023 Nov 1.
Amino acid-based surfactants are valuable compounds for cosmetic formulations. The chemical synthesis of acyl amino acids is conventionally performed by the Schotten-Baumann reaction using fatty acyl chlorides, but aminoacylases have also been investigated for use in biocatalytic synthesis with free fatty acids. Aminoacylases and their properties are diverse; they belong to different peptidase families and show differences in substrate specificity and biocatalytic potential. Bacterial aminoacylases capable of synthesis have been isolated from Burkholderia, Mycolicibacterium, and Streptomyces. Although several proteases and peptidases from S. griseus have been described, no aminoacylases from this species have been identified yet. In this study, we investigated two novel enzymes produced by S. griseus DSM 40236 . We identified and cloned the respective genes and recombinantly expressed an α-aminoacylase (EC3.5.1.14), designated SgAA, and an ε-lysine acylase (EC3.5.1.17), designated SgELA, in S. lividans TK23. The purified aminoacylase SgAA was biochemically characterized, focusing on its hydrolytic activity to determine temperature- and pH optima and stabilities. The aminoacylase could hydrolyze various acetyl amino acids at the N -position with a broad specificity regarding the sidechain. Substrates with longer acyl chains, like lauroyl amino acids, were hydrolyzed to a lesser extent. Purified aminoacylase SgELA specific for the hydrolysis of N -acetyl-l-lysine was unstable and lost its enzymatic activity upon storage for a longer period but could initially be characterized. The pH optimum of SgELA was pH 8.0. While synthesis of acyl amino acids was not observed with SgELA, SgAA catalyzed the synthesis of lauroyl-methionine.
基于氨基酸的表面活性剂是化妆品配方中很有价值的化合物。酰基氨基酸的化学合成通常通过使用脂肪酸酰氯的 Schotten-Baumann 反应进行，但也研究了使用游离脂肪酸的氨基酰化酶进行生物催化合成。氨基酰化酶及其性质多种多样；它们属于不同的肽酶家族，在底物特异性和生物催化潜力方面存在差异。能够进行合成的细菌氨基酰化酶已从伯克霍尔德氏菌、分枝杆菌和链霉菌中分离出来。尽管已经描述了来自 S. 灰色的几种蛋白酶和肽酶，但尚未鉴定出该物种的氨基酰化酶。在这项研究中，我们研究了 S. 灰色 DSM 40236 产生的两种新型酶。我们鉴定并克隆了相应的基因，并在 S. 在 lividans TK23 中重组表达了一种 α-氨基酰化酶（EC3.5.1.14），命名为 SgAA，和一种 ε-赖氨酸酰化酶（EC3.5.1.17），命名为 SgELA。纯化的氨基酰化酶 SgAA 的生化特性进行了研究，重点是其水解活性，以确定温度和 pH 最佳值和稳定性。该氨基酰化酶可以水解 N -位的各种乙酰氨基酸，对侧链具有广泛的特异性。具有较长酰基链的底物，如月桂酰氨基酸，水解程度较小。对 N -乙酰-l-赖氨酸水解特异性的纯化氨基酰化酶 SgELA不稳定，在长时间储存后会失去酶活性，但最初可以进行表征。SgELA 的 pH 最佳值为 pH 8.0。虽然 SgELA 没有观察到合成酰基氨基酸，但 SgAA 催化了月桂酰甲硫氨酸的合成。
