Laboratório de Imunopatologia Keizo Asami, Universidade Federal de Pernambuco (UFPE), 50780-901 Recife, Pernambuco, Brazil.
Bioresour Technol. 2010 Mar;101(6):1595-602. doi: 10.1016/j.biortech.2009.10.044. Epub 2009 Nov 27.
Invertase was covalently immobilized on polyurethane (PU), inox plate covered with plast-film layer and ferromagnetic azide-Dacron. The immobilization processes, physico-chemical parameters and a model for coupling reactions were studied. The preliminary studies for selection of the support showed that the best activity was obtained for PU treated with HCl, polyethylenimine and glutaraldehyde (156.7+/-4.9 U/g support). All plast-film-invertase derivatives did not show activity and the Dacron-invertase derivative showed an activity of 105.39 U/g support. The invertase immobilized in presence of substrate (10% w/v sucrose) was the most efficient (832.74+/-1.48 U/g support). The optimal pH was shifted from 4.5 (free enzyme) to 5.0 (immobilized derivative) and optimal temperature was not affected. Activation energy values of free enzyme, Dacron-invertase and PU-invertase were 32.4+/-0.34 kJ/mol, 33.4+/-0.36 kJ/mol and 44.0+/-0.67 kJ/mol, respectively. The PU-invertase could be used over 2 months without considerable activity loss (68.5% activity retention) and retained 12.6% (287.97+/-27.9U/g support) of the activity after five cycles.
将蔗糖酶共价固定在涂有塑料膜层和磁性叠氮化物涤纶的聚氨酯（PU）、不锈钢板上。研究了固定化过程、物理化学参数和偶联反应模型。选择载体的初步研究表明，经 HCl、聚乙烯亚胺和戊二醛处理的 PU 获得的酶活性最高（156.7+/-4.9 U/g 载体）。所有塑料膜-蔗糖酶衍生物均无活性，而涤纶-蔗糖酶衍生物的酶活性为 105.39 U/g 载体。在底物（10%w/v 蔗糖）存在下固定化的蔗糖酶最有效（832.74+/-1.48 U/g 载体）。最佳 pH 值从游离酶的 4.5（4.5）转移到固定化衍生物的 5.0（5.0），最佳温度不受影响。游离酶、涤纶-蔗糖酶和 PU-蔗糖酶的活化能值分别为 32.4+/-0.34 kJ/mol、33.4+/-0.36 kJ/mol 和 44.0+/-0.67 kJ/mol。PU-蔗糖酶可在无明显活性损失（保留 68.5%的活性）的情况下使用超过 2 个月，且在 5 次循环后仍保留 12.6%（287.97+/-27.9U/g 载体）的活性。
