Storey K B, Duncan J A, Chakrabarti A C
Department of Biology, Carleton University, Ottawa, Ontario, Canada.
Appl Biochem Biotechnol. 1990 Mar;23(3):221-36. doi: 10.1007/BF02942056.
Amyloglucosidase was covalently immobilized using two hydrophilic prepolymers: Hypol FHP 2002 (creates foams) and Hypol FHP 8190H (creates gels). The foamable prepolymer was superior as a support for enzyme immobilization. The percent activity immobilized in the polyurethane foams was 25 +/- 1.5%. Large substrates (greater than 200,000 daltons in mol wt) were hydrolyzed as effectively as smaller ones by the immobilized enzyme. The Km value of the foam-immobilized enzyme increased from 0.76 mg/mL (free) to 0.86 mg/mL (immobilized), whereas the Vmax dropped from 90.9 (free) to 12.4 nmol glucose/min/mL (immobilized). The long-term (2 mo) storage stability of amyloglucosidase was enhanced by immobilization in foams (70% activity retained; free enzyme only retained 50%). Immobilization also improved the enzyme stability to various denaturing agents (sodium chloride, urea, and ethanol). The immobilized enzyme exhibited increased stability compared to the free enzyme at high temperatures (95 degrees C). Both glycogen and starch could be utilized by the immobilized enzyme, indicating that this technique could prove useful for starch hydrolysis.
Hypol FHP 2002（产生泡沫）和Hypol FHP 8190H（产生凝胶）。可发泡的预聚物作为酶固定化的载体表现更优。固定在聚氨酯泡沫中的酶活性百分比为25±1.5%。固定化酶对大分子底物（分子量大于200,000道尔顿）的水解效果与小分子底物一样有效。泡沫固定化酶的Km值从0.76毫克/毫升（游离酶）增加到0.86毫克/毫升（固定化酶），而Vmax从90.9（游离酶）降至12.4纳摩尔葡萄糖/分钟/毫升（固定化酶）。通过固定在泡沫中，糖化酶的长期（2个月）储存稳定性得到提高（保留70%的活性；游离酶仅保留50%）。固定化还提高了酶对各种变性剂（氯化钠、尿素和乙醇）的稳定性。与游离酶相比，固定化酶在高温（95℃）下表现出更高的稳定性。固定化酶能够利用糖原和淀粉，这表明该技术在淀粉水解方面可能很有用。
