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固定化鲅鱼乙酰胆碱酯酶的制备及部分性质测定 总被引:3,自引:0,他引:3
酶的固定化是酶传感器制备过程中重要的1个环节.研究采用直接共价法固定鲅鱼乙酰胆碱酯酶(AChE).制备方法为:0.1g CNBr活化的Sepharose 4B凝胶用1mmol/L的HCl充分溶胀后,与活力为10U的AChE溶液混合,于4℃下150r/min振荡8h.所制备的固定化酶活力回收率较高(96%),对pH值和温度变化的适应能力均优于非固定化酶;在3个月保存期内,前者的活力损失13%,而后者的活力则下降89%.这说明固定过程能够大大提高AChE的抗逆性和保持酶活力的稳定,有利于酶传感器的制备. 相似文献
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When Pseudomonas aeruginosa PAO1 biofilms (attached to Sepharose surfaces) were subjected to dissolved Fe3+, most Fe was removed from solution within 25 h by surface complexation with negatively charged functional groups on the bacterial cell wall via a nucleation and mineralization process. Chemical formation of Fe-(hydr)oxides was partially responsible for dissolved Fe removal, which stemmed from a pH increase, facilitated by microbial activity. PAO1 used Fe3+ as an electron acceptor producing Fe2+ under localized anaerobic conditions over the first 50 h. The high ratio of Fe2+ to total Fe in solution produced a high proportion of Fe(II) in Fe precipitates; however, as the formation of Fe-(hydr)oxides started after 50 h, the Fe2+ content in solution began to diminish. Biofilms can so influence the local chemical conditions and metal speciation that the bulk solution phase is also affected, thereby mediating a wide-range (bio)geochemical cycling of iron. Long-term survival of natural biofilms, even under strict oligotrophic conditions, could have a broad lasting effect on the bulk geochemical environment. 相似文献
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