l-asparaginases (l-ASNases; EC 3.5.1.1) are aminohydrolases that catalyze the hydrolysis of l-asparagine (l-Asn) to l-aspartic acid and ammonia, resulting in the death of acute lymphoblastic leukemic cells and other blood cancer cells. In this study, Bacillus sonorensis (accession number MK523484) uncharacterized l-ASNase gene (accession number MN562875) was isolated by polymerase chain reaction (PCR), cloned into pET28a (+) vector, and expressed in Escherichia coli as a cytosolic protein. The recombinant enzyme was purified by affinity chromatography at 23.79-fold and 49.37% recovery. Denaturing polyacrylamide gel (10%) analysis of the purified enzyme resulted in a single protein band at 36 kDa that immunoreacted strongly with 6His-tag monoclonal antibody. The purified enzyme exhibited optimal activity at 45 °C and pH 7.0 and retained 92% and 85% of its initial activity after incubation for 60 min at 37 °C and 45 °C, respectively. The purified enzyme exhibited substrate specificity toward l-asparagine and low glutaminase activity (15.72%) toward l-glutamine at a concentration of 10 mM. The Km and Vmax values were 2.004 mM and 3723 µmol min¹⁻, respectively.

升-asparaginases（升-ASNases; EC 3.5.1.1）是催化的水解aminohydrolases升天冬酰胺（升-Asn）至升-天冬氨酸和氨，从而导致急性淋巴细胞白血病细胞和其它血液癌症细胞的死亡。在这项研究中，通过聚合酶链反应（PCR）分离了Bacillus sonorensis（登录号MK523484）未表征的1- ASNase基因（登录号MN562875），克隆到pET28a（+）载体中并在大肠杆菌中表达作为胞质蛋白。通过亲和色谱法以23.79倍和49.37％的回收率纯化重组酶。对纯化的酶进行变性聚丙烯酰胺凝胶分析（10％），得到一个36 kDa的单个蛋白带，该蛋白带与6His-tag单克隆抗体发生了强烈的免疫反应。纯化的酶在45°C和pH 7.0下表现出最佳活性，并分别在37°C和45°C孵育60分钟后保留其初始活性的92％和85％。纯化的酶底物展出朝向特异性升天冬酰胺和低谷氨酰胺酶活性（15.72％）朝向升谷氨酰胺以10mM的浓度。的公里和Vmax值分别为2.004 mM和3723微摩尔分钟^1-，分别。