Enzymatic Synthesis of Functional Oligosaccharides from Lactulose.

乳果糖具有广泛的用途;双歧因子在维持婴儿和成人的正常肠道菌群，减少脑病复发的频率，并允许在大多数此类患者中增加膳食蛋白质消耗，不太明确的含氮门体脑病严重恶化。在本报告中，本文报道了曲霉半乳糖苷酶催化乳果糖转半乳糖基化反应所形成的低聚糖的分离和性质。主要的三糖、四糖和五糖已通过活性炭柱和制备纸色谱法分离，并显示具有以下结构：O-D-吡喃半乳糖基-（1-6）-O-D-吡喃半乳糖基-（1-4）-D-果糖（TR），O-D-吡喃半乳糖基-（1-6）-O-D-吡喃半乳糖基-（1-6）-O-D-吡喃半乳糖基-（1-4）-D-果糖（TE），和O-D-吡喃半乳糖基-（1- 6）-O-D-吡喃半乳糖基-（1- 6）-O-D-吡喃半乳糖基-（1 - 6）-O-D-吡喃半乳糖基-（1- 4）-D-果糖（PE）。从25个曲霉种和24个曲霉菌株中筛选出一株曲霉Aspergillus S65，该菌株从乳果糖中积累了大量的低聚半乳糖。形成的最丰富的寡糖是TR和TE。罗伦隐球菌在含乳果糖的培养基中也能产生低聚糖。按总产量计算，三聚氰胺的产量为15.5%。形成的主要产物是迄今未描述的三糖，O-D-吡喃半乳糖基-（1-4）-O-D-吡喃半乳糖基-（1-4）-D-果糖。

Lactulose has acquired a broad range of usefulness; bifidus factor in maintaining the normal intestinal microflora of infant and also adult, reduction the frequency of recurrences of encephalophthy and permits increased dietary protein consumption in the great majority of such patients, less well defined severe exacerbations of nitrogenous portal-systemic encephalopathy.In this report, isolation and characterization of oligosaccharides formed by the transgalactosylation reaction of lactulose catalyzed by Aspergillus oryzae -galactosidase were described. Major Tri-, tetra- and pentasaccharide has been isolated by charcoal column and preparative paper chromatography and shown to have the structure: O- -D-galactopyranosyl-(1---6)-O- -D-galacto-pyranosyl-(1---4)-D-fructose(TR), O- -D-galactopyranosyl-(1---6)-O- -D-galacto-pyranosyl-(1---6)-O- -D-galactopyranosyl-(1---4)-D-fructose(TE), and O- -D-galactopyranosyl-(1---6)-O- -D-galactopylanosyl-(1---6)-O- -D-galactopyranosyl-(1---6)-O- -D-galactopyranosyl-(1---4)-D-fructose(PE).In attempt to produce oligosaccharides in medium containing lacturose, an Aspergillus oryzae S-65 screened from 25 aspergillus species and 24 Aspergillus oryzae strains accumulate in large quantities of galacto oligosaccharides from lactulose. The most abundant oligosaccharide formed were TR and TE. A Cryptococcus laurentii also produced oligosaccharides in lacturose containing medium. The yield of trisaccharides was 15.5 per cent based on total saccharides. The main product formed was A hitherto undescrided trisaccharide, O- -D-galactopyranosyl-(1---4)-O- -D-galactopyranosyl-(1---4)-D-fructose.