黄曲霉毒素解毒酶的固定化及其性质的研究  

Characterization of Immobilized Aflatoxin-detoxizyme

作　　者：刘大岭[1] 姚冬生[1] 黄炳贺 谢春芳[1] 梁郁强[1] 马林[3] 

机构地区：[1]暨南大学生命科技学院生物系,广州510632 [2]广东省技术开发中心,广州510070 [3]中山大学化学与化学工程学院有机所,广州510275

出　　处：《生物工程学报》2003年第5期603-607,共5页Chinese Journal of Biotechnology

基　　金：国家自然科学基金资助 (No .3 0 170 80 8);广东省自然科学基金重点项目基金资助 (No .0 10 418)~~

摘　　要：黄曲霉毒素是农作物常见的受污染的霉菌毒素 ,毒性大 ,稳定性高 ,是潜在的肝癌致癌物 ,对人的危害较大。该毒素的解毒与去毒一直是受到关注的问题。黄曲霉毒素解毒酶对黄曲霉毒素有特殊的去毒和降解作用 ,但是该酶的稳定性离解决实际问题尚有一段距离。报道了对黄曲霉毒素解毒酶的固定化 ,并对固定化处理后酶的稳定性、性质、催化活性、解毒活性进行了测定。结果表明 ,通过固定化操作酶的解毒活性被保留下来 ,酶的酸碱稳定性、热稳定性。Aflatoxins, found in contaminated food, are potent hepatocarcinogen. The aflatoxin detoxiczyme (ADTZ) isolated from the edible fungus Armillariella sp., detoxifies aflatoxin B1 (AFB1). This paper reports on the characterization of immobilized ADTZ using a hydrophobic adsorption method. The ADTZ was isolated from cryo homogenated fungus, previously cultivated at 24～28℃ for 20～30 days, using n alkyl amino agar beads. Various adsorption conditions of the enzyme to n alkyl or n octyl amino agar beads were carried out. The effects of enzyme immobilization on different alkyl amino agar beads, at different pH values (5.5～7.5), at different temperature (20～40℃) and at different salt concentrations were investigated. The enzyme activity was measured at OD 360 by reacting 133.3 ng/mL of AFB1 at 30℃ for 30 min with the immobilized ADTZ. The K m value of the immobilized enzyme, determined using Schematic Linewearver Burk plot, is 3.308×10 -3 mol/L, lower than that of free enzyme, which is 2.16×10 -6 mol/L. This indicated the affinity of the detoxiczyme to AFB1 decreased after immobilization. The immobilized enzyme activity in oil phase ( n hexane) was also studied with different concentration of water. After the treatment of the immobilized ADTZ, the toxin no longer causes liver toxicity in the rat toxicity test, no longer causes mutagenicity in Ames test and is no longer toxic in the chicken embryo test. Results also indicated that the pH stability, the thermostability and the freezing stability of ADTZ were improved after the immobilization.

关 键 词：黄曲霉毒素 解毒酶 固定化 稳定性 催化活性 

分 类 号：Q936[生物学—微生物学]