On the Enzyme Specificity for the Synthesis of Prebiotic Galactooligosaccharides
On the Enzyme Specificity for the Synthesis of Prebiotic Galactooligosaccharides
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益生元低聚半乳糖合成的酶特异性
DOI：
10.1007/978-81-322-1094-8_3
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
F. Plou
中科院分区：
文献类型：
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作者：
Bárbara Rodriguez;L. Fernández;Miguel Teixeira de Abreu;Paulina Urrutia;M. Fernández;A. Ballesteros;F. Plou
β-半乳糖苷酶催化转半乳糖基化反应，其中乳糖以及水解释放的葡萄糖和半乳糖作为半乳糖基受体，产生一系列低聚半乳糖 (GOS)。 GOS 是母乳中低聚糖的主要组成部分，负责母乳喂养婴儿肠道中双歧杆菌微生物群的形成。 GOS的生物活性取决于其化学组成、结构和聚合度。我们分析了各种 β-半乳糖苷酶的产物特异性，即来自乳酸克鲁维酵母、环状芽孢杆菌和米曲霉的β-半乳糖苷酶。环状芽胞杆菌β-半乳糖苷酶合成的主要产物仅包含β-(1→4)键，而乳酸克鲁维酵母合成的GOS主要存在β-(1→6)键。米曲霉β-半乳糖苷酶优先形成β-(1→6)键，β-(1→3)键比例较小。环状芽孢杆菌和乳酸克鲁维酵母 β-半乳糖苷酶产生近 45-50% (w/w) 的 GOS，而米曲霉酶产生的 GOS 低于 30% (w/w)。三种酶之间的另一个区别是产物的聚合度；特别是，对于富含二糖的 GOS 混合物，乳酸克鲁维酵母和米曲霉 β-半乳糖苷酶是最佳选择。相反，对于三糖和四糖含量高的 GOS 产品来说，环状芽孢杆菌酶是优选的。
β-Galactosidases catalyze transgalactosylation reactions in which lactose as well as the glucose and galactose released by hydrolysis serve as galactosyl acceptors yielding a series of galactooligosaccharides (GOS). GOS constitute the major part of oligosaccharides in human milk and are responsible of the formation of a Bifidus microbiota in the intestine of milk-fed babies. The bioactive properties of GOS depend on their chemical composition, structure, and polymerization degree. We have analyzed the product specificity of various β-galactosidases, namely, those from Kluyveromyces lactis, Bacillus circulans, and Aspergillus oryzae. The major products synthesized by B. circulans β-galactosidase contained only β-(1 → 4) bonds, whereas the enzyme from K. lactis synthesized GOS with major presence of β-(1 → 6) linkages. The A. oryzae β-galactosidase formed preferentially β-(1 → 6) bonds, with minor proportion of β-(1 → 3). B. circulans and K. lactis β-galactosidases produce nearly 45–50 % (w/w) GOS, whereas the A. oryzae enzyme produces less than 30 % (w/w). Another difference between the three enzymes was the polymerization degree of products; in particular, for a GOS mixture enriched in disaccharides, K. lactis and A. oryzae β-galactosidases are the best choices. In contrast, the B. circulans enzyme would be preferable for a GOS product with a high trisaccharides and tetrasaccharides content.