Characterization of a glycoside hydrolase family 1 β-galactosidase from hot spring metagenome with transglycosylation activity.

Richa Gupta, Tanvi Govil, Neena Capalash, Prince Sharma

Department of Biotechnology, Panjab University, Chandigarh 160014, India.

Applied biochemistry and biotechnology 2012 Nov

filter terms:

A novel, thermostable, alkalophilic β-D-galactosidase (Mbgl) was isolated from a metagenome of geothermal springs in northern Himalayan region of India. Mbgl was 447 amino acids in size and had conserved catalytic residues E170 and E358, indicating that it belonged to family 1 of glycosyl hydrolases showing maximum homology (89 %) with uncharacterized β-galactosidase of Eubacterium, Meiothermus ruber DSM1279. Temperature and pH optima of Mbgl were 65 °C and 8.0 respectively, and it retained 80 % activity even at pH 10.0. Mbgl was active as a homotetramer, recognized β-(1,4)-D-galactoside as the preferred glycosidic bond, and preferentially hydrolyzed pNPgal with K(m) 3.33 mM and k(cat) 2,000 s(-1). It displayed high transglycosylation activity with wide acceptor specificity including hexoses and pentoses leading to the formation of prebiotic galacto-oligosaccharides whereas its lactose hydrolysis potential was low.

Citation

Richa Gupta, Tanvi Govil, Neena Capalash, Prince Sharma. Characterization of a glycoside hydrolase family 1 β-galactosidase from hot spring metagenome with transglycosylation activity. Applied biochemistry and biotechnology. 2012 Nov;168(6):1681-93