豆浆脂肪氧合酶测定方法的优化及酶动力学的研究  

Method Optimization for the Determination of Lipoxygenase in Soybean Milk and the Evaluation of Its Kinetics

作　　者：夏宁 王晓琪 严文冰 章智华 郭爽 杨文君 赵雪[2] 石彦国[1] XIA Ning;WANG Xiao-qi;YAN Wen-bing;ZHANG Zhi-hua;GUO Shuang;YANG Wen-jun;ZHAO Xue;SHI Yan-guo(Scbeol of Food Engineering, Harbin University of Commerce, Harbin 150076, China;Key Laboratory of Soybean Biology, Northeast Agricultural University, Harbin 150030, China;School of Food Science and Engineering, South China University of Technology, Guangzhou 510641, China)

机构地区：[1]哈尔滨商业大学食品工程学院,黑龙江哈尔滨150076 [2]东北农业大学大豆生物学教育部重点实验室,黑龙江哈尔滨150030 [3]华南理工大学食品科学与工程学院,广东广州510641

出　　处：《大豆科学》2018年第5期769-775,共7页Soybean Science

基　　金：国家重点研发计划(2017YFD0101302-5);黑龙江省科学基金(C2018026);辽宁省肉类加工与质量安全控制工程技术研究中心开放课题(2018001)

摘　　要：本文以前人所确定的大豆中LOX酶活力测定方法为基础,对生豆浆中LOX活力测定方法进行稳定性方面的优化,研究热处理过程、不同浓度豆浆对LOX活力的影响,并确定LOX的最大反应速率、米氏速率常数和不同金属离子抑制剂及激活剂等酶反应动力学参数,研究结果表明:待测样品稀释300倍时,LOX活力值的变化趋势较为明显,且结果稳定;对10个不同地域大豆进行制浆,在300倍稀释倍数下测定不同加热温度的豆浆发现,LOX活力在40℃时最高,当加热至80℃时完全失活,故选择对LOX测定方法进行样品稀释300倍,加热至40℃的优化处理。优化后的方法较其它已报到方法相比,能够快速、准确地测出不同豆种所制豆浆中LOX活力值,且试验结果重复性好,稳定性高。通过对LOX酶促反应动力学的研究,确定了LOX酶促反应最大反应速率V_(max)=1. 99ΔA·min^(-1),R^2=0. 942 8,米氏速率常数K_m=452. 49μmol·L^(-1);金属离子中,钙离子、镁离子对LOX起抑制作用,当锌离子在浓度为0. 002 mol·L^(-1)时,对LOX起抑制作用,而当锌离子浓度大于0. 004 mol·L^(-1)时,则对LOX起激活作用。Based on the method of determining the activity of LOX enzyme in soybean, we optimized the stability of the method of determining the activity of LOX in raw soybean milk, and studied the effect of heat treatment and different concentration of soybean milk on the activity of LOX in this paper. The maximum reaction rate of LOX, the Michlet rate constant and the kinetic parameters of enzyme reaction such as different metal ion inhibitors and activators were determined. The results showed that the change trend of LOX activity was obvious when the sample was diluted 300 times. The results were stable, and the results of soybean pulping in 10 different regions were determined at 300 times dilution times by different heating temperatures. The activity of LOX in soybean milk was highest at 40℃ and completely inactivated when heated to 80℃. Compared with other reported methods, the optimized method can measure the activity of LOX in soybean milk of different soybean varieties quickly and accurately, and the experimental results are reproducible and stable By studying the kinetics of enzymatic reaction of LOX, the maximum reaction rate of LOX was deter-mined： Vmax =l. 99△A·min^-l ,R^2 =0.942 8,Km =452.49 μmol·L^-l. In metal ions, Ca^2＋ and Mg^2＋ had an inhibitory effect on LOX. At the concentration of 0. 002 mol·L^-l, the LOX was inhibited, and when the concentration of zinc ion was greater than 0.004 mol·L^-1, the LOX was activated.

关 键 词：豆浆 大豆脂肪氧合酶(LOX) 酶促反应动力学 抑制剂 激活剂 

分 类 号：TS201.25[轻工技术与工程—食品科学]