Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China.
J Agric Food Chem. 2010 Mar 10;58(5):3184-90. doi: 10.1021/jf904367r.
A beta-mannanase gene, man5AP13, was cloned from Phialophora sp. P13 and expressed in Pichia pastoris. The deduced amino acid sequence of the mature enzyme, MAN5AP13, had highest identity (53%) with the glycoside hydrolase family 5 beta-mannanase from Bispora sp. MEY-1. The purified recombinant beta-mannanase was acidophilic and acid stable, exhibiting maximal activity at pH 1.5 and retaining >60% of the initial activity over the pH range 1.5-7.0. The optimum temperature was 60 degrees C. The specific activity, K(m) and V(max) for locust bean gum substrate were 851 U/mg, 2.5 mg/mL, and 1667.7 U/min.mg, respectively. The enzyme had excellent activity and stability under simulated gastric conditions, and the released reducing sugar of locust bean gum was significantly enhanced by one-fold in simulated gastric fluid containing pepsin in contrast to that without pepsin. All these properties make MAN5AP13 a potential additive for use in the food and feed industries.
从青霉属 P13 中克隆了一个β-甘露聚糖酶基因 man5AP13，并在毕赤酵母中表达。成熟酶 MAN5AP13 的推导氨基酸序列与来自双孢属 MEY-1 的糖苷水解酶家族 5β-甘露聚糖酶具有最高的同一性（53%）。纯化的重组β-甘露聚糖酶具有嗜酸性和酸稳定性，在 pH 值为 1.5 时表现出最大活性，并在 pH 值为 1.5-7.0 的范围内保留超过初始活性的 60%。最适温度为 60°C。该酶对槐豆胶底物的比活性、K(m)和 V(max)分别为 851 U/mg、2.5 mg/mL 和 1667.7 U/min·mg。该酶在模拟胃液条件下具有良好的活性和稳定性，与不含胃蛋白酶的模拟胃液相比，在含有胃蛋白酶的模拟胃液中槐豆胶的释放还原糖显著提高了一倍。所有这些特性使 MAN5AP13 成为食品和饲料工业中潜在的添加剂。
