An esterase gene, estA1, was cloned from Alteromonas sp. 39-G1 isolated from the Beaufort Sea. The gene is composed of 1,140 nucleotides and codes for a 41,190 Da protein containing 379 amino acids. As a result of a BLAST search, the protein sequence of esterase EstA1 was found to be identical to Alteromonas sp. esterase (GenBank: PHS53692). As far as we know, no research on this enzyme has yet been conducted. Phylogenetic analysis showed that esterase EstA1 was a member of the bacterial lipolytic enzyme family IV (hormone sensitive lipases). Two deletion mutants (Δ20 and Δ54) of the esterase EstA1 were produced in Escherichia coli BL21 (DE3) cells with part of the N-terminal of the protein removed and His-tag attached to the C-terminal. These enzymes exhibited the highest activity toward p-nitrophenyl (pNP) acetate (C₂) and had little or no activity towards pNP-esters with acyl chains longer than C₆. Their optimum temperature and pH of the catalytic activity were 45°C and pH 8.0, respectively. As the NaCl concentration increased, their enzyme activities continued to increase and the highest enzyme activities were measured in 5 M NaCl. These enzymes were found to be stable for up to 8 h in the concentration of 3-5 M NaCl. Moreover, they have been found to be stable for various metal ions, detergents and organic solvents. These salt-tolerant and chemical-resistant properties suggest that the enzyme esterase EstA1 is both academically and industrially useful.

中文翻译：

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从海洋细菌交替单胞菌中分离出的新型耐盐酯酶的表征。39-G1。

一种酯酶基因，estA1 ，是从交替单胞菌中克隆出来的。从波弗特海分离出的 39-G1。该基因由 1,140 个核苷酸组成，编码 41,190 Da 的蛋白质，包含 379 个氨基酸。作为 BLAST 搜索的结果，发现酯酶 EstA1 的蛋白质序列与交替单胞菌属相同。酯酶（GenBank：PHS53692）。据我们所知，尚未对这种酶进行任何研究。系统发育分析表明，酯酶 EstA1 是细菌脂肪分解酶家族 IV（激素敏感性脂肪酶）的成员。在大肠杆菌中产生了酯酶 EstA1 的两个缺失突变体（Δ20 和 Δ54）BL21 (DE3) 细胞去除了部分蛋白质的 N 端，并将 His 标签连接到 C 端。这些酶对p - nitrophenyl ( p NP) acetate (C ₂ )表现出最高活性，对酰基链长于 C _6的p NP-酯几乎没有活性. 它们的催化活性的最适温度和pH分别为45℃和pH 8.0。随着 NaCl 浓度的增加，它们的酶活性继续增加，并且在 5 M NaCl 中测量到最高的酶活性。发现这些酶在 3-5 M NaCl 的浓度下最多可稳定 8 小时。此外，已发现它们对各种金属离子、洗涤剂和有机溶剂稳定。这些耐盐和耐化学物质的特性表明，酯酶 EstA1 在学术和工业上都有用。