Spangenberg P, André C, Dion M, Rabiller C, Mattes R
Unité de Recherches en Biocatalyse (Unité CNRS 2230), Faculte des Sciences et des Techniques, Nantes, France.
Carbohydr Res. 2000 Oct 20;329(1):65-73. doi: 10.1016/s0008-6215(00)00170-1.
We have studied the potential of several newly cloned alpha-galactosidases to catalyze the regioselective synthesis of disaccharides using 4-nitrophenylgalactoside as a donor. The kinetics of the reactions were followed by in situ NMR spectroscopy. The following thermophilic enzymes have been tested: Aga A and an isoenzyme Aga B obtained from the strain KVE39 and Aga 285 from the strain IT285 of Bacillus stearothermophilus; Aga T is an alpha-galactosidase from Thermus brockianus (strain IT360). Two other non-thermophilic alpha-galactosidases have also been evaluated: Aga 1 (Streptococcus mutans, strain Ingbritt) and Raf A (Escherichia coli, strain D1021). For all of the enzymes studied, high regioselectivity was observed leading to two (1 --> 6)-disaccharides: 4-nitrophenyl alpha-D-galactopyranosyl-(1--> 6)-alpha-D-galactopyranoside and methyl alpha-D-galactopyranosyl-(1--> 6)-alpha-D-galactopyranoside, which were obtained in 54% (Aga B) and 20% (Aga T) yields, respectively.
我们研究了几种新克隆的α-半乳糖苷酶利用4-硝基苯基半乳糖苷作为供体催化区域选择性合成二糖的潜力。通过原位核磁共振光谱跟踪反应动力学。已测试了以下嗜热酶：从嗜热脂肪芽孢杆菌KVE39菌株获得的Aga A和同功酶Aga B，以及从嗜热栖热菌IT285菌株获得的Aga 285；Aga T是来自嗜热栖热菌（IT360菌株）的α-半乳糖苷酶。还评估了另外两种非嗜热α-半乳糖苷酶：Aga 1（变形链球菌，Ingbritt菌株）和Raf A（大肠杆菌，D1021菌株）。对于所研究的所有酶，均观察到高区域选择性，生成两种（1→6）-二糖：4-硝基苯基α-D-吡喃半乳糖基-（1→6）-α-D-吡喃半乳糖苷和甲基α-D-吡喃半乳糖基-（1→6）-α-D-吡喃半乳糖苷，其产率分别为54%（Aga B）和20%（Aga T）。
