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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11847

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Data final: 2009Tem arquivos: SimAssunto: search.filters.subject.α-Galactosidase

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    Extracellular α-Galactosidase from Debaryomyces hansenii UFV-1 and Its use in the hydrolysis of raffinose oligosaccharides
    (Journal of Agricultural and Food Chemistry, 2006-02-17) Rezende, Sebastião T. de; Marques, Virgínia M.; Trevizano, Larissa M.; Passos, Flávia M. L.; Oliveira, Maria G. A.; Bemquerer, Marcelo P.; Oliveira, Jamil S.; Guimarães, Valéria M.; Viana, Pollyanna A.
    Raffinose oligosaccharides (RO) are the factors primarily responsible for flatulence upon ingestion of soybean-derived products. ROs are hydrolyzed by α-galactosidases that cleave α-1,6-linkages of α-galactoside residues. The objectives of this study were the purification and characterization of extracellular α-galactosidase from Debaryomyces hansenii UFV-1. The enzyme purified by gel filtration and anion exchange chromatographies presented an Mr value of 60 kDa and the N-terminal amino acid sequence YENGLNLVPQMGWN. The Km values for hydrolysis of pNPαGal, melibiose, stachyose, and raffinose were 0.30, 2.01, 9.66, and 16 mM, respectively. The α-galactosidase presented absolute specificity for galactose in the α-position, hydrolyzing pNPGal, stachyose, raffinose, melibiose, and polymers. The enzyme was noncompetitively inhibited by galactose (Ki = 2.7 mM) and melibiose (Ki = 1.2 mM). Enzyme treatments of soy milk for 4 h at 60 °C reduced the amounts of stachyose and raffinose by 100%.
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    Covalent immobilization of α-Galactosidase from Penicillium griseoroseum and its application in Oligosaccharides Hydrolysis
    (Applied Biochemistry and Biotechnology, 2008-10-21) Falkoski, Daniel Luciano; Guimarães, Valéria Monteze; Queiroz, Marisa Vieira de; Araújo, Elza Fernandes de; Almeida, Maíra Nicolau de; Barros, Everaldo Gonçalves de; Rezende, Sebastião Tavares de
    Partially purified α-Galactosidase from Penicillium griseoroseum was immobilized onto modified silica using glutaraldehyde linkages. The effective activity of immobilized enzyme was 33%. Free and immobilized α-galactosidase showed optimal activity at 45 °C and pH values of 5 and 4, respectively. Immobilized α-galactosidase was more stable at higher temperatures and pH values. Immobilized α-galactosidase from P. griseoroseum maintained 100% activity after 24 h of incubation at 40 °C, while free enzyme showed only 32% activity under the same incubation conditions. Defatted soybean flour was treated with free and immobilized α-galactosidase in batch reactors. After 8 h of incubation, stachyose was completely hydrolyzed in both treatments. After 8 h of incubation, 39% and 70% of raffinose was hydrolyzed with free and immobilized α-galactosidase respectively. Immobilized α-galactosidase was reutilized eight times without any decrease in its activity.
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    Characterization and biotechnological application of an acid α-galactosidase from Tachigali multijuga Benth. seeds
    (Phytochemistry, 2008-10-02) Fialho, Lílian da Silva; Guimarães, Valéria Monteze; Callegari, Carina Marin; Reis, Angélica Pataro; Barbosa, Daianny Silveira; Borges, Eduardo Euclydes de Lima; Moreira, Maurilio Alves; Rezende, Sebastião Tavares de
    Tachigali multijuga Benth. seeds were found to contain protein (364 mg g−1 dwt), lipids (24 mg g−1 dwt), ash (35 mg g−1 dwt), and carbohydrates (577 mg g−1 dwt). Sucrose, raffinose, and stachyose concentrations were 8.3, 3.0, and 11.6 mg g−1 dwt, respectively. α-Galactosidase activity increased during seed germination and reached a maximum level at 108 h after seed imbibition. The α-galactosidase purified from germinating seeds had an Mr of 38,000 and maximal activity at pH 5.0–5.5 and 50 °C. The enzyme was stable at 35 °C and 40 °C, but lost 79% of its activity after 30 min at 50 °C. The activation energy (Ea) values for p-nitrophenyl-α-d-galactopyranoside (pNPGal) and raffinose were 13.86 and 4.75 kcal mol−1, respectively. The Km values for pNPGal, melibiose, raffinose, and stachyose were 0.45, 5.37, 39.62 and 48.80 mM, respectively. The enzyme was sensitive to inhibition by HgCl2, SDS, AgNO3, CuSO4, and melibiose. d-Galactose was a competitive inhibitor (Ki = 2.74 mM). In addition to its ability to hydrolyze raffinose and stachyose, the enzyme also hydrolyzed galactomannan.