Institut für Mikrobiologie der Georg-August Universität Göttingen, 3400 Göttingen, and Arbeitsbereich Biotechnologie I, Technische Mikrobiologie, Technische Universität Hamburg-Harburg, Denickestrasse 15, 2100 Hamburg 90, Germany.
Appl Environ Microbiol. 1991 Aug;57(8):2317-23. doi: 10.1128/aem.57.8.2317-2323.1991.
A bacterial glucoamylase was purified from the anaerobic thermophilic bacterium Clostridium thermosaccharolyticum and characterized. The enzyme, which was purified 63-fold, with a yield of 36%, consisted of a single subunit with an apparent molecular mass of 75 kDa. The purified enzyme was able to attack alpha-1,4- and alpha-1,6-glycosidic linkages in various alpha-glucans, liberating glucose with a beta-anomeric configuration. The purified glucoamylase, which was optimally active at 70 degrees C and pH 5.0, attacked preferentially polysaccharides such as starch, glycogen, amylopectin, and maltodextrin. The velocity of oligosaccharide hydrolysis decreased with a decrease in the size of the substrate. The K(m) values for starch and maltose were 18 mg/ml and 20 mM, respectively. Enzyme activity was not significantly influenced by Ca, EDTA, or alpha- or beta-cyclodextrins.
从厌氧嗜热细菌热解梭菌中纯化并表征了一种细菌葡萄糖淀粉酶。该酶经过 63 倍的纯化，产率为 36%，由一个具有 75 kDa 表观分子量的单一亚基组成。纯化的酶能够攻击各种α-葡聚糖中的α-1,4-和α-1,6-糖苷键，释放具有β-端构型的葡萄糖。纯化的葡萄糖淀粉酶在 70°C 和 pH 值为 5.0 时具有最佳活性，优先攻击淀粉、糖原、支链淀粉和麦芽糊精等多糖。低聚糖水解的速度随底物大小的减小而降低。淀粉和麦芽糖的 K(m) 值分别为 18mg/ml 和 20mM。酶活性不受 Ca、EDTA 或α-或β-环糊精的显著影响。
