双醛氧化纤维素固定化木瓜蛋白酶及酶学性质的研究

以双醛氧化纤维素为载体固定化木瓜蛋白酶,研究了固定化酶的制备条件、微观结构及酶学性质。结果表明:固定化时间4h,固定化温度4℃,酶/载体=1:3000(g:g)时,固定化酶的活力最高为50.9U/g。红外光谱和扫描电镜对固定化酶的微观结构研究表明,双醛氧化纤维素的醛基与木瓜蛋白酶的氨基发生共价反应形成固定化酶。与游离酶相比,木瓜蛋白酶经过固定化后,热稳定性和耐酸性增强,与底物酪蛋白的亲和力降低,固定化酶重复使用5次后,相对酶活力为55.1%。 

Study on the immobilization of papain by dialdehyde oxycellulose and enzymatic properties

Dialdehyde oxycellulose was prepared as the carrier to immobilize papain.The preparation conditions,microstructure and enzymatic properties of the immobilized enzyme were studied.The results showed that the maximum activity of immobilized papain was 50.9U/g under the optimal immobilization conditions:immobilization time 4h,4℃ and 1:3000 enzyme/carrier ratio(w/w).The microstructure of immobilized enzyme,which was studied by infrared spectrum and scanning electron microscope analysis,showed that the aldehyde group of dialdehyde oxycellulose could react with the amino group of the papain to form immobilized enzyme.Compared with free enzyme,the heat stability and acid resistance of immobilized papain were increased;the affinity with substance casein of dialdehyde oxycellulose immobilized papain was decreased.After being reused five times,the relative enzyme activity was 55.1%.