Hydrolysis of β-d-glucopyranosyl fluoride to α-d-glucose catalyzed by Aspergillus niger α-d-glucosidase
作者:Edward J. Hehre、Hirokazu Matsui、Curtis F. Brewer
DOI:10.1016/0008-6215(90)84282-y
日期:1990.4
-glucosyl fluoride and not from a contaminating trace of α- d -glucosyl fluoride, and is catalyzed by the α- d -glucosidase and not by an accompanying trace of β- d -glucosidase or glucoamylase. Maltotriose competitively inhibits the hydrolysis, and β- d -glucosyl fluoride in turn competitively inhibits the hydrolysis of p-nitrophenyl α- d -glucopyranoside, indicating that β- d -glucosyl fluoride is bound
摘要黑曲霉α-d-葡萄糖苷酶结晶且对β-d-葡萄糖苷没有可检测的活性,催化β-d-葡萄糖吡喃糖基氟的缓慢水解形成α-d-葡萄糖。β-d-葡萄糖基氟,对硝基苯基α-d-吡喃葡萄糖苷和α-d-吡喃葡萄糖基氟化物水解的最大初始速率V为0.27、0.75和78.5μmol.min-1.mg-1,分别具有0.0068、1.44和41.3的相应V / K常数。独立的证据表明,该反应源自β-d-葡萄糖基氟化物,而不是源自痕量的α-d-葡萄糖基氟化物,并且是由α-d-葡萄糖苷酶催化,而不是由伴随的β-痕量催化。 d-葡糖苷酶或葡糖淀粉酶。麦芽三糖竞争性地抑制水解,β-d-葡萄糖基氟又竞争性地抑制对硝基苯基α-d-葡萄糖吡喃糖苷的水解,表明β-d-葡萄糖基氟与已知的α-葡萄糖苷酶底物结合在同一位点。当前的发现提供了新的证据,即α-葡萄糖苷酶不限于α-d-葡萄糖基底物或提供保留构型的反应。他们强烈支持这样的概