Department of Biochemistry and Molecular Biology-A, Faculty of Biology, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia , Campus Espinardo, E-30100 Murcia, Spain.
J Agric Food Chem. 2012 Aug 1;60(30):7450-6. doi: 10.1021/jf3014102. Epub 2012 Jul 17.
The possibility of incorporating N-acetylneuraminic acid (Neu5Ac) in infant formulas and other functional foods has opened up the need to synthesize N-acetylneuraminic acid using N-acetylneuraminate lyases (NALs) by reversible aldol condensation of pyruvate and N-acetyl-d-mannosamine. Until now, NALs have been cloned from pathogenic microorganisms; however, this Article describes the expression and characterization of an N-acetylneuraminate lyase from the Staphylococcus carnosus TM300, a GRAS microorganism used in fermented meat. ScNAL showed a high level of expression in E. coli (403 mg L(-1) culture). This, combined with its simple two-step purification procedure, the highest recovery described to date (86%), its kinetic parameters, which are in the same order of magnitude as best reported NALs, and its optimum pH and temperature, make ScNAL a promising and cheap biocatalyst. To confirm its biotechnological potential, the Neu5Ac was synthesized in 3 h in simple industrial working conditions with a high degree of conversion (94%).
将 N-乙酰神经氨酸（Neu5Ac）纳入婴儿配方奶粉和其他功能性食品的可能性，使得通过丙酮酸和 N-乙酰-D-甘露糖胺的可逆醛醇缩合来使用 N-乙酰神经氨酸裂解酶（NAL）合成 N-乙酰神经氨酸成为必要。到目前为止，NAL 已经从致病性微生物中克隆出来；然而，本文描述了来自肉葡萄球菌 TM300 的 N-乙酰神经氨酸裂解酶的表达和特性，该菌是一种用于发酵肉的 GRAS 微生物。ScNAL 在大肠杆菌中表现出高水平的表达（403mg/L 培养物）。这一点，再加上其简单的两步纯化程序，是迄今为止报道的最高回收率（86%），其动力学参数与最佳报道的 NAL 处于同一数量级，以及其最适 pH 值和温度，使 ScNAL 成为一种有前途且廉价的生物催化剂。为了确认其生物技术潜力，在简单的工业工作条件下，在 3 小时内以高转化率（94%）合成了 Neu5Ac。
