Síntesis de oligosacáridos fucosilados por vía enzimática mediante reacciones de fucosilación
The composition of human milk is very complex, has a large number of bioactive compounds, including oligosaccharides (OS). These compounds can be free or conjugated. The free OS are the third component of human milk after lactose and lipids, in recent decades, more than 130 OS have been isolated and...
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| Formato: | tesis de maestría |
| Estado: | Versión publicada |
| Fecha de publicación: | 2011 |
| País: | México |
| Recursos: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:5x21tf57b |
| Acesso em linha: | https://doi.org/10.24275/uami.5x21tf57b |
| Access Level: | acceso abierto |
| Palavra-chave: | info:eu-repo/classification/LEM/Carbohidratos info:eu-repo/classification/LEM/Prebióticos info:eu-repo/classification/LEM/Leche materna info:eu-repo/classification/LEM/Oligosacáridos -- Síntesis info:eu-repo/classification/LEM/Biotecnología info:eu-repo/classification/cti/6 |
| Resumo: | The composition of human milk is very complex, has a large number of bioactive compounds, including oligosaccharides (OS). These compounds can be free or conjugated. The free OS are the third component of human milk after lactose and lipids, in recent decades, more than 130 OS have been isolated and identified. The OS of human milk play an important role in protection from infectious diseases, researches suggests that they are partly responsible for reducing the risk of infections in infants who are breastfed by favoring the growth of intestinal flora determined also are potent inhibitors of the adherence of pathogens on the epithelial surface of the intestine. There is now a growing interest in the ability of human milk OS, especially fucosyloligosaccharides to protect babies from enteric pathogens during early development. It is known that fucosyl-oligosaccharides have a link terminal α (1-2) have protective activity against Campylobacter jejuni and inhibit adhesion of Escherichia coli toxin. The biological importance of these compounds has generated interest, principally to produce and apply them in the food industry as a bioactive component in powder milk. There have been two main alternatives for the synthesis of OS, chemical synthesis and enzymatic synthesis. Despite the low yields obtained using glycosidases for the production of OS. An alternative is still studied as the chemical synthesis uses toxic solvents, and catalysts are not allowed in food regulation and the use of glycosyl-transferases is limited by low availability of the enzyme. The aim of this study was the synthesis of fucosylated oligosaccharides by fucosylation reactions using glycosyl-hydrolase exclusively. Reaction conditions were established for the synthesis of fucosyl-lactose by an enzymatic way, using hyperthermophilic β-glycosidase GLY 001-02 and α-fucosidase of Bos taurus using the PNP-F as a substrate donor and lactose as an acceptor substrate. Trisaccharide was obtained, which was subsequently hydrolyzed to known monosaccharides present in its structure and verify the presence of fucose. Furthermore, were established the reaction conditions for the synthesis of fucosylated disaccharides using α-galactosidase of "Beano", α-glucosidase of Saccharomyces cerevisiae and hyperthermophilic β-glycosidase GLY 001-02. We were synthesized eight different disaccharide: a disaccharide α-galactosyl-fucose using α-galactosidase of "Beano", melibiose and fucose as a donor and acceptor substrate, but it was impossible to purify for study; four disaccharides using α-glucosidase of Saccharomyces cerevisiae, using maltose as donor substrate and fucose as an acceptor substrate, these obtained in greater quantity was purified and identified by enzymatic hydrolysis as α-glucosyl-fucose; finally were synthesized three fucosylated disaccharides β-galactosyl-fucose, using hyperthermophilic β-glycosidase, using lactose as donor and fucose as an acceptor substrate, with probable prebiotic activity. Besides the presence of fucose in these OS is of great interest for further study microbial adhesion as this monosaccharide is recognized by adhesins of pathogenic bacteria. Synthesize fucosylated compounds was achieved by reaction fucosylation exclusively with hydrolases, using as donor substrate PNP-F as the acceptor substrate lactose, demonstrating the feasibility of the reaction. However, it is necessary to establish more efficient strategies that result in higher yields, as use of organic solvents or synthesis under saturated conditions of substrates to reduce the water activity and reaction fucosylation favor. The results generated great expectations and so far the studies on probiotics have focused on fructo-oligosaccharides and galacto-oligosaccharides, bypassing the OS of breast milk are known but its importance in the development of intestinal microbiota of infants, in addition to the high concentration of fucosylated oligosaccharides in breast milk suggests that they bring greater benefits to health. |
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