Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences , Beijing 100081, People's Republic of China.
J Agric Food Chem. 2014 Dec 31;62(52):12686-94. doi: 10.1021/jf504239h. Epub 2014 Dec 19.
Thermophilic endo-polygalacturonases with high catalytic efficiency are of great interest in the food and feed industries. This study identified an endo-polygalacturonase gene (pg7fn) of glycoside hydrolase family 28 in the thermophilic fungus Thielavia arenaria XZ7. Recombinant PG7fn produced in Pichia pastoris is distinguished from other enzyme counterparts by its high functional temperature (60 °C) and specific activity (34382 ± 351 U/mg toward polygalacturonic acid). The enzyme exhibited good pH stability (pH 3.0-8.0) and resistance to pepsin and trypsin digestion and had a significant effect on disaggregation of soybean meal. Addition of 1 U/g PG7fn increased the pectin bioavailability by 19.33%. The excellent properties described above make PG7fn valuable for applications in the food and feed industries. Furthermore, a comparative study showed that N-glycosylation improved the thermostability and catalytic efficiency of PG7fn.
嗜热内切聚半乳糖醛酸酶具有较高的催化效率，在食品和饲料工业中具有重要的应用价值。本研究在嗜热真菌 Thielavia arenaria XZ7 中鉴定了一种糖苷水解酶家族 28 的内切聚半乳糖醛酸酶基因（pg7fn）。毕赤酵母表达的重组 PG7fn 与其他酶的区别在于其较高的功能温度（60°C）和比活性（对聚半乳糖醛酸的比活性为 34382±351 U/mg）。该酶具有良好的 pH 稳定性（pH3.0-8.0）和对胃蛋白酶和胰蛋白酶消化的抗性，对大豆粕的解聚有显著作用。添加 1 U/g 的 PG7fn 可使果胶的生物利用率提高 19.33%。上述优良特性使 PG7fn 在食品和饲料工业中有很高的应用价值。此外，比较研究表明，N-糖基化提高了 PG7fn 的热稳定性和催化效率。
