Chen L, Sadek M, Stone B A, Brownlee R T, Fincher G B, Høj P B
School of Biochemistry, La Trobe University, Bundoora, Vic., Australia.
Biochim Biophys Acta. 1995 Nov 15;1253(1):112-6. doi: 10.1016/0167-4838(95)00157-p.
The stereochemical course of hydrolysis of Laminaria digitata laminarin and barley (1-->3, 1-->4)-beta-glucan by barley (1-->3)-beta-glucanase (E.C. 3.2.1.39) isoenzyme GII and (1-->3, 1-->4)-beta-glucanase (EC 3.2.1.73) isoenzyme EII, respectively, has been determined by 1H-NMR. Both enzymes catalyse hydrolysis with retention of anomeric configuration (e-->e) and may therefore operate via a double displacement mechanism. We predict that all other members of Family 17 of beta-glycosyl hydrolases also follow this stereochemical course of hydrolysis.
利用核磁共振氢谱（1H-NMR）分别测定了海带（Laminaria digitata）海带多糖和大麦（1→3, 1→4）-β-葡聚糖被大麦（1→3）-β-葡聚糖酶（E.C. 3.2.1.39）同工酶GII和（1→3, 1→4）-β-葡聚糖酶（EC 3.2.1.73）同工酶EII水解的立体化学过程。这两种酶均催化水解反应并保留异头构型（e→e），因此可能通过双取代机制起作用。我们预测β-糖基水解酶家族17的所有其他成员也遵循这种立体化学水解过程。
