海沃德猕猴桃巯基蛋白酶的催化特性与稳定性  

Catalytic characteristics and stability of thiol protease from Hayward kiwifruit

作　　者：张倩[1] 陈彦[1,2] 林晓艳[1,2] 林金凤[1] 

机构地区：[1]西南科技大学材料工程与科学学院,四川绵阳621010 [2]生物质材料教育部工程研究中心,四川绵阳621010

出　　处：《食品工业科技》2012年第6期205-207,224,共4页Science and Technology of Food Industry

基　　金：四川省科技厅科技支撑项目(2011NZ0004)

摘　　要：对以海沃德猕猴桃残次果提取的巯基蛋白酶进行了动力学研究,考察了一些外加剂对酶活的影响,同时初步探讨了酶液的稳定性。结果表明:以酪蛋白为底物的猕猴桃巯基蛋白酶的Km值为6.56×10-3mmol,Vmax为163.93mg·mL-1·min-1;在其底物浓度为1.0g/L时,该酶的最适温度和pH分别为55℃和5.5;L-半胱氨酸、2-巯基乙醇、硫代硫酸钠、EDTA以及葡萄糖等外加剂对酶具有明显的激活效果,且EDTA的激活作用最强;抗坏血酸、碘乙酸和过氧化氢等外加剂对酶则具有抑制作用。在最适酶促反应条件下,于4℃温度存放的酶液活性随时间延长呈急剧的降低,并以pH为3.5存放条件下的降低最少,约可保存80%的酶活性。The kinetics of thiol protease（TP）from defective Hayward fruits were investigated, as well as the impact of some additives on the activity and stability of enzyme solution.The results showed that Km value of TP was 6.56 x 10-3 mmol, casein as substrate,and its Vmax was 163.93mg · mL -1· min-1 .The optimum conditions of TP reactions were 55℃ and pH 5.5 at L0g/L casein concentration.The additives such as L-cysteine, 2-mercaptoethanol （2-ME）, sodium thiosulfate, EDTA and glucose had significant promotion effect on TP activity, among which EDTA exhibited the best activation.However,the addition of ascorbic acid （AA）, iodoacetic acid and hydrogen peroxide had inhibitory effect.Under the optimum enzymatic reaction conditions, the activity of protease had a sharp drop when storage time of protease solution increased at 4cC.The drop was least when pH was 3.5, and about 80% of the activity could still be reserved.

关 键 词：猕猴桃 巯基蛋白酶 催化 抑制剂 激活剂 

分 类 号：TS255.1[轻工技术与工程—农产品加工及贮藏工程]