Beta-1,3-galactosyl-N-acetylhexosamine phosphorylase from Bifidobacterium bifidum DSM 20082: characterization, partial purification and relation to mucin degradation.
A new enzyme has been characterized in a cell-free extract of Bifidobacterium bifidum that catalysed the reversible phosphorolytic cleavage of beta-1,3-galacto-oligosaccharides. In the presence of Pi, the phosphorolysis reaction was favoured and was accompanied by a Walden reaction. Cleavage of the beta-glycosidic linkage gave an alpha-galactoside derivative (alpha-D-galactose 1-phosphate). The enzyme possesses a high specificity for beta-D-galactosido-(1, 3)-N-acetylglucosamine and beta-D-galactosido-(1, 3)-N-acetylgalactosamine. This purified intracellular enzyme had an estimated molecular mass of 140 kDa. The galactophosphorolytic activity on disaccharides was optimal at pH 6-6.5 and the reverse reaction was optimal at pH 5.5-6. The temperature optimum for phosphorolysis and the reverse reaction was approx. 50-55 degrees C. This enzyme is of particular interest in degrading some beta-D-Gal(1, 3) linkages and should be classified as EC 2.4.1.-.
Derensy-Dron
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D
Laboratoire de Chimie Biologique, UMR No. 111 CNRS, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France.
Krzewinski
F
F
Brassart
C
C
Bouquelet
S
S
D000818:Animals; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism; D001644:Bifidobacterium / Q000201:enzymology*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000378:metabolism; D005695:Galactosephosphates / Q000737:chemistry / Q000378:metabolism; D005700:Galactosyltransferases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009077:Mucins / Q000378:metabolism*; D010766:Phosphorylation; D013379:Substrate Specificity; D013552:Swine; D013696:Temperature
D001426:Bacterial Proteins; D004187:Disaccharides; D005695:Galactosephosphates; D009077:Mucins; C029973:galactose-1-phosphate; D005700:Galactosyltransferases; C118176:beta-1,3-galactosyl-N-acetylhexosamine phosphorylase