Open AccessCloning and characterization of a novel α‐galactosidase from Bifidobacterium breve 203 capable of synthesizing Gal‐α‐1,4 linkage
Author(s) -
Zhao Han,
Lu Lili,
Xiao Min,
Wang Qinpeng,
Lu Yu,
Liu Chunhui,
Wang Peng,
Kumagai Hidehiko,
Yamamoto Kenji
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01246.x
Subject(s) - melibiose , bifidobacterium breve , chemistry , trisaccharide , glycosyl , biochemistry , stereochemistry , monosaccharide , hydrolysis , enzyme , bifidobacterium , lactobacillus , fermentation , maltose
A novel α‐galactosidase gene ( aga2 ) was cloned from Bifidobacterium breve 203. It contained an ORF of 2226‐bp nucleotides encoding 741 amino acids with a calculated molecular mass of 81.5 kDa. The recombinant enzyme Aga2 was heterogeneously expressed, purified and characterized. Regarding substrate specificity for hydrolysis, Aga2 was highly active towards p ‐nitrophenyl‐α‐ d ‐galactopyranoside ( p NPG). The K m value for p NPG was estimated to be 0.27 mM and for melibiose it was estimated to be 4.3 mM. Aga2 was capable of catalyzing transglycosylation as well as hydrolysis. The enzyme synthesized a trisaccharide (Gal‐α‐1, 4‐Gal‐α‐1, 6‐Glc) using melibiose as a substrate. It was a new oligosaccharide produced by glycosidase and contained Gal‐α‐1,4 linkage, a novel galactosidic link formed by microbial α‐galactosidase. In the presence of p NPG as a donor, Aga2 was able to catalyze glycosyl transfer to various acceptors including monosaccharides, disaccharides and sugar alcohols.