Formation of Oligosaccharides from Lactose byBacillus circulans β-Galactosidase

α-d-Glcp-(1↔1)-β-d-Galp-containing oligosaccharides, novel products from lactose by the action of β-galactosidase

“…Evidence for structure 3.1B was found in the ROESY spectrum, showing a strong ROE I H-1,II% H-1 and a weak ROE II H-1,I H-2. The substitution of Glc at O-2 is supported by the chemical shift of the anomeric proton of residue I (a H-1, 5.45 ppm) which is characteristic for a 2-substituted a-Glc residue [8]. No 2-substituted hexose was found in the methylation analysis, probably because of the small amount of this compound present in Fraction 3.1.…”

“…In total, two 4-substituted Galp residues were found (H-1, l 4.478 with H-4, l 4.18; H-1, l 4.60 with H-4, l 4.18). The typical chemical shifts of two H-1b signals below l 4.50 (l 4.478 and 4.439) indicated the presence of two Galp residues linked to O-4 of a Glcp residue [8,12] (structure 3.1A).…”

“…Various parameters such as source of the enzyme, substrate concentration, pH, and temperature can influence the transgalactosylation and thereby the final yields of the different compounds formed [5]. The structures of oligogalactosylated glucoses reported so far range from dimers to pentamers [1,[6][7][8][9]. Depending on the biological origin of the b-galactosidase applied, different linkages be- Branched Glc residues also occur, whereas the oligogalactose fragments contain mainly (1 4) or (1 6) linkages.…”

The Discoidin Domain ofBacillus circulansβ-Galactosidase Plays an Essential Role in Repressing Galactooligosaccharide Production

“…[1][2][3][4] Hence a number of attempts to isolate -galactosidases with high transgalactosylation activities from various microorganisms have been reported, [5][6][7][8][9][10][11][12][13] and genes that encode -galactosidases, [13][14][15][16][17][18][19][20][21][22][23][24] including those of B. circulans ATCC 31382, 13,24) have been cloned. However, the lack of a crystal structure as well as a lack of knowledge of the multimeric and monomeric structures of a number of high molecular weight -galactosidases, except for Escherichia coli -galactosidase, 25) has been a drawback to developing an understanding of the mechanism of transgalactosylation.…”

Causes of the Production of Multiple Forms of β-Galactosidase byBacillus circulans

“…GOS are important prebiotics that enhance the proliferation of intestinal bifidobacteria and lactobacilli in the colon, which in turn promote human health by protecting individuals against infection, reducing the accumulation of harmful bacteria/toxic compounds, and facilitating the normal function of the gut. [8][9][10][11] Because of this, a number of studies have reported attempts to isolate a -galactosidase with high transgalactosylation activity from various microorganisms, [4][5][6][7][8] including Bacillus circulans, 12,13) Bifidobacterium adolescentis, 14) Lactobacillus reuteri, 15,16) and others. [17][18][19][20] Furthermore, the genes that encode -galactosidases from bacteria, including B. circulans, 21) Bifidobacterium bifidum [22][23][24][25] / Bifidobacterium infantis, 22,[26][27][28] L. reuteri, 29) L. plantarum, 30) and others, 20,31) have been cloned and sequenced, and the enzymes have been overexpressed in heterologous cells.…”