Manzanares P, de Graaff L H, Visser J
Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, The Netherlands.
Enzyme Microb Technol. 1998 Apr;22(5):383-90. doi: 10.1016/s0141-0229(97)00207-x.
An enzyme with beta-galactosidase activity and three proteins exhibiting alpha-galactosidase activity were purified from a culture filtrate of Aspergillus niger grown on arabinoxylan. beta-galactosidase, optimally active at pH 4 and 60-65 degrees C, was active against p-nitrophenyl-beta-D-galactopyranoside, lactose, and pectic galactan. It was not able to release galactose from sugar beet pectin or lemon pectin. Its action on pectic galactan was increased by the presence of beta-galactanase. The three forms of alpha-galactosidase activity that showed different molecular masses and pIs were found to have the same mass after deglycosylation with N-glycanase F and to be the same protein based on their N-terminal amino acid sequence data. The purified alpha-galactosidase was shown to be different from alpha-galactosidase A from A. niger. This confirmed the existence of at least two different alpha-galactosidases in A. niger. alpha-Galactosidase, optimally active at pH 4.5 and 50-55 degrees C, was active toward p-nitrophenyl-alpha-D-galactopyranoside, melibiose, raffinose, stachyose, and locust bean gum, on which substrate it exhibited synergism with beta-mannanase.
从在阿拉伯木聚糖上生长的黑曲霉培养滤液中纯化出一种具有β-半乳糖苷酶活性的酶和三种具有α-半乳糖苷酶活性的蛋白质。β-半乳糖苷酶在pH 4和60 - 65℃时活性最佳，对对硝基苯基-β-D-吡喃半乳糖苷、乳糖和果胶半乳聚糖有活性。它不能从甜菜果胶或柠檬果胶中释放半乳糖。β-半乳糖苷酶的存在会增强其对果胶半乳聚糖的作用。三种形式的α-半乳糖苷酶活性表现出不同的分子量和等电点，在用N-聚糖酶F去糖基化后发现具有相同的质量，并且根据它们的N端氨基酸序列数据是相同的蛋白质。纯化的α-半乳糖苷酶显示与黑曲霉的α-半乳糖苷酶A不同。这证实了黑曲霉中至少存在两种不同的α-半乳糖苷酶。α-半乳糖苷酶在pH 4.5和50 - 55℃时活性最佳，对硝基苯基-α-D-吡喃半乳糖苷、蜜二糖、棉子糖、水苏糖和刺槐豆胶有活性，在该底物上它与β-甘露聚糖酶表现出协同作用。
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