Group of Fungal Genetic Engineering, Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, 117312 Moscow, Russia.
Laboratory of Medical Biotechnology, Institute of Biomedical Chemistry, 119121 Moscow, Russia.
Int J Mol Sci. 2021 Dec 20;22(24):13632. doi: 10.3390/ijms222413632.
L-asparaginase (L-ASNase) is a biotechnologically relevant enzyme for the pharmaceutical, biosensor and food industries. Efforts to discover new promising L-ASNases for different fields of biotechnology have turned this group of enzymes into a growing family with amazing diversity. Here, we report that thermophile from of the Bacteroidetes/Chlorobi group possesses two L-ASNases-bacterial type II (MrAII) and plant-type (MrAIII). The current study is focused on a novel L-ASNase MrAII that was expressed in , purified and characterized. The enzyme is optimally active at 70 °C and pH 9.3, with a high L-asparaginase activity of 1530 U/mg and L-glutaminase activity ~19% of the activity compared with L-asparagine. The kinetic parameters K and V for the enzyme were 1.4 mM and 5573 µM/min, respectively. The change in MrAII activity was not significant in the presence of 10 mM Ni, Mg or EDTA, but increased with the addition of Cu and Ca by 56% and 77%, respectively, and was completely inhibited by Zn, Fe or urea solutions 2-8 M. MrAII displays differential cytotoxic activity: cancer cell lines K562, Jurkat, LnCap, and SCOV-3 were more sensitive to MrAII treatment, compared with normal cells. MrAII represents the first described enzyme of a large group of uncharacterized counterparts from the Chlorobi-Ignavibacteriae-Bacteroidetes clade.
L-天冬酰胺酶（L-ASNase）是一种与生物技术相关的酶，在制药、生物传感器和食品工业中具有重要作用。为了在不同的生物技术领域发现新的有前途的 L-ASNases，人们已经将这组酶发展成为一个具有惊人多样性的不断壮大的家族。在这里，我们报告了一种来自拟杆菌门/绿菌门的嗜热菌 ，它拥有两种 L-ASNases-细菌 II 型（MrAII）和植物型（MrAIII）。目前的研究集中在一种新型的 L-ASNase MrAII 上，该酶在 中表达、纯化并进行了特性分析。该酶在 70°C 和 pH 9.3 下具有最佳活性，L-天冬酰胺酶活性高达 1530 U/mg，L-谷氨酰胺酶活性比 L-天冬酰胺高约 19%。该酶的动力学参数 K 和 V 分别为 1.4 mM 和 5573 µM/min。在存在 10 mM Ni、Mg 或 EDTA 时，MrAII 活性变化不显著，但添加 Cu 和 Ca 可分别增加 56%和 77%，而 2-8 M 的 Zn、Fe 或尿素溶液可完全抑制其活性。MrAII 表现出不同的细胞毒性活性：与正常细胞相比，K562、Jurkat、LnCap 和 SCOV-3 等癌细胞系对 MrAII 处理更为敏感。MrAII 代表了绿菌-无壁菌-拟杆菌门群中一大组未被描述的酶的首个描述。
