Hydrolysis of Oligosaccharides by a Thermostable α-Galactosidase from Termitomyces eurrhizusReport as inadecuate




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1

State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing 100193, China

2

Shaanxi Microbiology Research Institute, No. 76 Xiying Road, Xi’an 710043, China

3

College of Food Science and Technology, Nanjing Agricultural University, Weigang, Nanjing 210095, China

4

School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China



These authors contributed equally to this work.





*

Authors to whom correspondence should be addressed.



Academic Editor: Vladimír Křen

Abstract 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. View Full-Text

Keywords: characterization; degradation; ITS; Termitomyces eurrhizus; TLC characterization; degradation; ITS; Termitomyces eurrhizus; TLC





Author: Weiwei Zhang 1,†, Fang Du 2,†, Li Wang 1, Liyan Zhao 3, Hexiang Wang 1,* and Tzi Bun Ng 4,*

Source: http://mdpi.com/



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