Kulminskaya Anna A, Arand Michael, Eneyskaya Elena V, Ivanen Dina R, Shabalin Konstantin A, Shishlyannikov Sergei M, Saveliev Andrew N, Korneeva Olga S, Neustroev Kirill N
Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Gatchina, Orlova Rosha, St. Petersburg 188350, Russia.
Biochim Biophys Acta. 2003 Aug 21;1650(1-2):22-9. doi: 10.1016/s1570-9639(03)00187-0.
1H-NMR analysis was applied to investigate the hydrolytic activity of Aspergillus awamori inulinase. The obtained NMR signals and deduced metabolite pattern revealed that the enzyme cleaves off only fructose from inulin and does not possess transglycosylating activity. Kinetics for the enzyme hydrolysis of inulooligosaccharides with different degree of polymerization (d.p.) were recorded. The enzyme hydrolyzed both beta2,1- as well as beta2,6-fructosyl linkages in fructooligosaccharides. From the k(cat)/K(m) ratios obtained with inulooligosaccharides with d.p. from 2 to 7, we deduce that the catalytic site of the inulinase contains at least five fructosyl-binding sites and can be classified as exo-acting enzyme. Product analysis of inulopentaose and inulohexaose hydrolysis by the Aspergillus inulinase provided no evidence for a possible multiple-attack mode of action, suggesting that the enzyme acts exclusively as an exoinulinase.
应用1H-NMR分析来研究泡盛曲霉菊粉酶的水解活性。所获得的NMR信号和推导的代谢物模式表明，该酶仅从菊粉中切割下果糖，不具有转糖基化活性。记录了不同聚合度（d.p.）的低聚果糖酶促水解的动力学。该酶水解低聚果糖中的β2,1-以及β2,6-果糖基键。根据用聚合度为2至7的低聚果糖获得的k(cat)/K(m)比值，我们推断菊粉酶的催化位点至少包含五个果糖基结合位点，可归类为外切酶。泡盛曲霉菊粉酶对菊粉五糖和菊粉六糖水解的产物分析没有提供可能的多重攻击作用模式的证据，表明该酶仅作为外切菊粉酶起作用。
