Manzanares P, de Graaff L H, Visser J
Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, The Netherlands.
FEMS Microbiol Lett. 1997 Dec 15;157(2):279-83. doi: 10.1111/j.1574-6968.1997.tb12785.x.
An enzyme with alpha-L-rhamnosidase activity was purified by anion exchange chromatography from an Aspergillus niger commercial preparation. The alpha-L-rhamnosidase was shown to be N-glycosylated, and had a molecular mass of 85 kD on sodium dodecylsulfate-polyacrylamide gel electrophoresis of which approximately 12% was contributed by carbohydrate. The enzyme was optimally active at pH 4.5 and 65 degrees C. When tested towards p-nitrophenyl-alpha-L-rhamnopyranoside it showed Km and Vmax values of 2.9 mM and 20.6 U mg-1, respectively whereas it was inhibited competitively by L-rhamnose (Ki 3.5 mM). Substrate specificity studies showed alpha-L-rhamnosidase to be active both on alpha-1,2 and alpha-1,6 linkages to beta-D-glucose. Moreover, the enzyme was able to release L-rhamnose from geranyl-beta-D-rutinoside and 2-phenylethyl-beta-D-rutinoside.
从黑曲霉商业制剂中通过阴离子交换色谱法纯化出一种具有α-L-鼠李糖苷酶活性的酶。该α-L-鼠李糖苷酶显示为N-糖基化，在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上的分子量为85 kD，其中约12%由碳水化合物贡献。该酶在pH 4.5和65℃时活性最佳。当用对硝基苯基-α-L-鼠李吡喃糖苷进行测试时，其Km和Vmax值分别为2.9 mM和20.6 U mg-1，而L-鼠李糖对其有竞争性抑制作用（Ki 3.5 mM）。底物特异性研究表明，α-L-鼠李糖苷酶对与β-D-葡萄糖的α-1,2和α-1,6键均有活性。此外，该酶能够从香叶基-β-D-芸香糖苷和2-苯乙基-β-D-芸香糖苷中释放出L-鼠李糖。
