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Updated: Jun 28, 2026
Tracing Gene Expression Through Detection of β-galactosidase Activity in Whole Mouse Embryos
Published on: June 26, 2018
A novel alpha-galactosidase from Bifidobacterium bifidum with transgalactosylating properties: gene molecular cloning
Theodoros Goulas1, Athanasios Goulas, George Tzortzis
1Department of Food Biosciences, School of Chemistry, Food Biosciences and Pharmacy, The University of Reading, P.O. Box 226, Whiteknights, Reading, RG6 6AP, UK. t.goulas@reading.ac.uk
Abstract:
A genomic library of Bifidobacterium bifidum (NCIMB 41171) DNA was constructed in Escherichia coli RA11r (melA(-)B(+)) and one alpha-galactosidase encoding gene was isolated. Conceptual translation combined with insertional mutagenesis analysis indicated an open reading frame (ORF) of 759 amino acid (aa) residues encoding an alpha-galactosidase (named as MelA) of 82.8 kDa. Partial purification and characterisation showed that the enzyme had an apparent native molecular mass of approximately 243 kDa and a subunit size of approximately 85 kDa. The enzyme belongs to glycosyl hydrolases 36 family with high aa sequence similarities (approximately 73%) to other known alpha-galactosidases of bifidobacterial origin. Under optimum pH conditions for activity (pH 6.0) and high melibiose concentration (40% w/v), the enzyme was able to form oligosaccharides with degree of polymerisation (DP) > or = 3 at higher concentration than DP = 2, with a total yield of 20.5% (w/w).
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