Hydrolysis of Oligosaccharides by a Thermostable α-Galactosidase from Termitomyces eurrhizus

International Journal of Molecular Sciences

Weiwei Zhang³  Fang Du⁴  Li Wang³  Liyan Zhao²  Hexiang Wang³  Tzi Bun Ng¹ 

[1] School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, ChinaCollege of Food Science and Technology, Nanjing Agricultural University, Weigang, Nanjing 210095, China;State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing 100193, China;Shaanxi Microbiology Research Institute, No. 76 Xiying Road, Xi’an 710043, China;

关键词: characterization;    degradation;    ITS;    Termitomyces eurrhizus;    TLC;   

DOI  :  10.3390/ijms161226159

来源: mdpi

【 摘 要 】

The genus of Termitomyces purchased from the market has been identified as Termitomyces eurrhizus using the Internal Transcribed Spacer (ITS) method. An α-galactosidase from T. eurrhizus (TEG), a monomeric protein with a molecular mass of 72 kDa, was purified 146 fold by employing ion exchange chromatography and gel filtration. The optimum pH and temperature was 5.0 and 60 °C, respectively. TEG was stable over pH 2–6, and also exhibited good thermostablility, retaining 100% of the original activity after incubation at 60 °C for 2 h. Inhibition of the enzyme activity by N-bromosuccinimide (NBS) constituted evidence for an essential role of tryptophan in the catalytic action of the isolated enzyme. Besides 4-nitro-phenyl α-d-galactophyranoside (pNPGal), natural substrates could also be effectively hydrolyzed by TEG. Results of thin-layer chromatography (TLC) revealed complete enzymatic hydrolysis of raffinose and stachyose to galactose at 50 °C within 6 h. These properties of TEG advocate its utilization for elevating the nutritional value of soymilk.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.