Viana Pollyanna A, de Rezende Sebastião T, Marques Virgínia M, Trevizano Larissa M, Passos Flávia M L, Oliveira Maria G A, Bemquerer Marcelo P, Oliveira Jamil S, Guimarães Valéria M
BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, 36570-000, Brazil.
J Agric Food Chem. 2006 Mar 22;54(6):2385-91. doi: 10.1021/jf0526442.
Raffinose oligosaccharides (RO) are the factors primarily responsible for flatulence upon ingestion of soybean-derived products. ROs are hydrolyzed by alpha-galactosidases that cleave alpha-1,6-linkages of alpha-galactoside residues. The objectives of this study were the purification and characterization of extracellular alpha-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 pNP alphaGal, melibiose, stachyose, and raffinose were 0.30, 2.01, 9.66, and 16 mM, respectively. The alpha-galactosidase presented absolute specificity for galactose in the alpha-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 degrees C reduced the amounts of stachyose and raffinose by 100%.
棉子糖低聚糖（RO）是摄入大豆制品后导致肠胃胀气的主要因素。RO 可被α-半乳糖苷酶水解，该酶能切断α-半乳糖苷残基的α-1,6-键。本研究的目的是从汉逊德巴利酵母UFV-1中纯化并鉴定胞外α-半乳糖苷酶。通过凝胶过滤和阴离子交换色谱法纯化的该酶，其Mr值为60 kDa，N端氨基酸序列为YENGLNLVPQMGWN。对pNPαGal、蜜二糖、水苏糖和棉子糖水解的Km值分别为0.30、2.01、9.66和16 mM。该α-半乳糖苷酶对α位的半乳糖具有绝对特异性，可水解pNPGal、水苏糖、棉子糖、蜜二糖和聚合物。该酶受到半乳糖（Ki = 2.7 mM）和蜜二糖（Ki = 1.2 mM）的非竞争性抑制。豆浆在60℃下经该酶处理4小时后，水苏糖和棉子糖的含量降低了100%。
