Oligosaccharides from lactose

Ganzle MG. Enzymatic synthesis of galacto-oligosaccharides and other lactose deriwitives (hetero-oligosaccharides) from lactose. Int Dairy J 2012 22(2) 116—22. 

Because reduction of the oligosaccharide occurs in the reductive-amination reaction, affinity adsorbents prepared by this route contain one glycosyl residue fewer than the original oligosaccharide. Adsorbents having such ligands may have low utility. The structure of the product obtained from lactose and 2-aminoethylpoly(acrylamide) by the reductive-amination route is shown in 6. 

In a more recent study (Asp et al. 1980), six oligosaccharides from hydrolyzed lactose milk which had been treated with K. lactis lactase were isolated from their structure, it was concluded that the enzyme had high transglycosylation activity with specificity for the formation of /3-(l,6)-galactosidic bonds. 

NeuSAc is a weak inhibitor of classical sialidases but does not act at all on the trans-sialidases. Correspondingly, the 2,3-difluoro derivative of NeuSAc, forming a covalent intermediate with sialidases and trans-sialidases (see later) was required at high concentrations (20 mM) to inactivate the enzyme completely Since trans-sialidases possess a lactose-binding site in their active center (as described next), lactose and its derivatives, especially lactitol, inhibit the sialic acid transfer of the enzyme from T. cruzi. Oligosaccharides from the mucins of this trypanosome can also inhibit the transfer of sialic acid to, for example, the substrate A-acetyllactosa-mine. It should be noted that heavy metal ions, especially merciuy, are potent inhibitors of sialidases and trans-sialidases. The latter enzymes do not require calcium ions, in contrast to some siaUdases. " " " ... 

Sugar alcohols can be prepared by hydrogenation of reducing mono-, di- and oligosaccharides. Sorbitol and mannitol are obtained from sucrose, maltitol from maltose and lactitol from lactose. Maltose is more expensive than sucrose while lactose, obtained from whey, potentially is an inexpensive raw material. 

Stevenson DE, Stanley RA, Fumeaux RH. Oligosaccharide and alkyl beta-galactopyranoside synthesis from lactose with Caldocellum saccharolyticum beta-glycosidase. Enzyme Microb Technol 1996 18(8) 544—9. 

Oligosaccharide N-acryloyl-glycosylamines, required for co-polymerization with acrylamide, have been synthesised in high yield from the corresponding free oligosaccharides (e, lactose, lacto-N-tetraose, and lacto-N-fucopentaose I and II) by amination [(NH4)2C03-H20] and aqrlation [CH2=CHCOCl - NaHCOj -MeOH]. ... 

Most bacteria in the genus Clostridia are able to secrete a variety of carbohydrate-degrading enzymes (Lee et al. 1985), which enable them to directly saccharify a variety of polysaccharides (cellulose, starch, xylan, pectin, etc.) and oligosaccharides (cellobiose, lactose, maltose, etc.). This is a clear advantage over Zymomonas and modified E. coli for the production of biofuels from Kgnocellulosic biomass, as the latter bacteria are... 

In agreement with the occurrence of Neu5Gc in colostrum and milk oligosaccharides from bovine and porcine sources, transfer from CMP-Neu5Gc to lactose could be demonstrated (Bartholomew et al. 1973, Carlson et al. 1973 a). 

Although the principal oligosaccharide of milk is lactose, this disacchaiide is accompanied by smaller amounts of other oligosaccharides, which can be separated from lactose by adsorption on activated carbon and elution with dilute acetic acid. The amounts vary somewhat with the mammalian species. In human milk, the concentration, exclusive of lactose, is about 3 g per liter. Preparative chromatography on carbon-Celite and cellulose columns has led to the isolation of live oligosaccharides in pure form (see Table X). 

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