State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China.
PLoS One. 2013 Apr 19;8(4):e62306. doi: 10.1371/journal.pone.0062306. Print 2013.
Most invertases identified to date have optimal activity at acidic pH, and are intolerant to neutral or alkaline environments. Here, an acid invertase named uninv2 is described. Uninv2 contained 586 amino acids, with a 100 amino acids N-terminal domain, a catalytic domain and a C-terminal domain. With sucrose as the substrate, uninv2 activity was optimal at pH 4.5 and at 45°C. Removal of N-terminal domain of uninv2 has shifted the optimum pH to 6.0 while retaining its optimum temperaure at 45°C. Both uninv2 and the truncated enzyme retained highly stable at neutral pH at 37°C, and they were stable at their optimum pH at 4°C for as long as 30 days. These characteristics make them far superior to invertase from Saccharomyces cerevisiae, which is mostly used as industrial enzyme.
迄今为止鉴定的大多数转化酶在酸性 pH 下具有最佳活性，并且不能耐受中性或碱性环境。在这里，描述了一种酸性转化酶，称为 uninv2。Uninv2 包含 586 个氨基酸，具有 100 个氨基酸的 N 端结构域、催化结构域和 C 端结构域。以蔗糖为底物时，uninv2 的活性在 pH4.5 和 45°C 时最佳。去除 uninv2 的 N 端结构域会将最佳 pH 值转移到 6.0，同时保持其在 45°C 的最佳温度。Uninv2 和截短的酶在中性 pH 值 37°C 下都保持高度稳定，并且在其最佳 pH 值 4°C 下可稳定 30 天以上。这些特性使它们远远优于大多数用作工业酶的酿酒酵母中的转化酶。
