A New alpha-Galactosidase from Thermoacidophilic Alicyclobacillus sp A4 with Wide Acceptor Specificity for Transglycosylation

作者：Wang, Huimin; Ma, Rui; Shi, Pengjun; Xue, Xianli; Luo, Huiying; Huang, Huoqing; Bai, Yingguo; Yang, Peilong; Yao, Bin^*

来源：Applied Biochemistry and Biotechnology, 2014, 174(1): 328-338.

DOI：10.1007/s12010-014-1050-8

• alpha-Galactosidase
• Alicyclobacillus sp A4
• Transglycosylation
• Wide acceptor specificity

An alpha-galactosidase gene (gal36A4) of glycosyl hydrolase family 36 was identified in the genome of Alicyclobacillus sp. A4. It contains an ORF of 2,187 bp and encodes a polypeptide of 728 amino acids with a calculated molecular mass of 82.6 kDa. Deduced Gal36A4 shows the typical GH36 organization of three domains-the N-terminal beta-sheets, the catalytic (beta/alpha)(8)-barrels, and the C-terminal antiparallel beta-sheet. The gene product was produced in Escherichia coli and showed both hydrolysis and transglycosylation activities. The optimal pH for hydrolysis activity was 6.0, and a stable pH range of 5.0-11.0 was found. The enzyme had a temperature optimum of 60 A degrees C. It is specific for alpha-1,6-glycosidic linkages and had a K (m) value of 1.45 mM toward pNPGal. When using melibiose as both donor and acceptor of galactose, Gal36A4 showed the transfer ratio of 23.25 % at 96 h. With respect to acceptor specificity, all tested monosaccharides, disaccharides, and oligosaccharides except for D-xylose and L-arabinose were good acceptors for transglycosylation. Thus, Gal36A4 may find diverse applications in industrial fields, especially in the food industry.

• 出版日期2014-9
• 单位中国农业科学院