黑美人马铃薯结合态和游离态多酚氧化酶的酶学性质研究  

Research on Enzymatic Properties of Membrane Bound and Soluble Polyphenol Oxidases in Black Beauty Potatoes

作　　者：刘辉[1,2] 卢扬 李俊[1] 范士杰[1] 王立新[3] 王辉 LIU Hui;LU Yang;LI Jun;FAN Shi-jie;WANG Li-xin;WANG Hui(Biotechnology Institute of Guizhou Academy of Agricultural Sciences,Guiyang 550006,China;Guizhou Key Laboratory of Agricultural Biotechnology,Guiyang 550006,China;Bijie Agricultural Technology Promotion Station,Bijie 551700,China)

机构地区：[1]贵州省农业科学院生物技术研究所,贵州贵阳550006 [2]贵州省农业生物技术重点实验室,贵州贵阳550006 [3]贵州省毕节市农业技术推广站,贵州毕节551700

出　　处：《保鲜与加工》2021年第10期1-7,共7页Storage and Process

基　　金：国家自然科学基金(31860461);国审马铃薯新品种黔芋7号示范及推广应用(黔科合成果[2020]1Y020);贵州省薯类产业技术创新人才基地项目[黔人领发(2016)22]。

摘　　要：为有效控制马铃薯加工过程中的酶促褐变,以黑美人马铃薯块茎为原料,分别提取游离态多酚氧化酶(sPPO)和膜结合态多酚氧化酶(mPPO)粗酶,并进行酶学性质研究。结果表明,黑美人马铃薯sPPO和mPPO的最大吸收波长分别为403 nm和406 nm。sPPO最适反应pH值为7,最适反应温度为25℃;mPPO最适反应pH值为7,最适反应温度为30℃。以绿原酸和间苯二酚为底物时,sPPO和mPPO均未检测到酶活力;以邻苯二酚为底物时,sPPO、mPPO的米氏常数(Km)分别为39.423、35.291 mmol/L,最大反应速度(Vmax)分别为0.019、0.290 mmol·L^(-1)·min^(-1);以焦性没食子酸为底物时,sPPO、mPPO的Km分别为205.896、205.067 mmol/L,Vmax分别为0.008、22.321 mmol·L^(-1)·min^(-1)。亚硫酸钠、抗坏血酸对sPPO和mPPO酶活力抑制作用明显;植酸、草酸、柠檬酸和EDTA对sPPO和mPPO酶活力也有不同程度的抑制。以上结果说明:sPPO和mPPO酶学性质存在较大差异,mPPO酶活力要显著高于sPPO,建议在利用黑美人马铃薯进行加工时,重点考虑mPPO对酶促褐变的影响。In this study,the soluble(sPPO)and membrane bound(mPPO)polyphenol oxidases were prepared from black beauty potatoes and the enzymatic properties were comparatively investigated,aiming to effectively control enzymatic browning during potatoes processing.Results showed that the maximum absorption wavelengths of sPPO and mPPO were 403 nm and 406 nm,respectively.The optimum reaction temperatures of sPPO and mPPO were 25℃and 30℃respectively with the same optimum reaction pH value of 7.The sPPO and mPPO showed no activity using chlorogenic acid or resorcinol as substrates.Michaelis constants(Km)of sPPO and mPPO were 39.423 mmol/L and 35.291 mmol/L with catechol as substrate,and the maximum enzyme speeds(Vmax)were 0.019 mmol·L^(-1)·min^(-1) and 0.290 mmol·L^(-1)·min^(-1),respectively.When employing pyrogallic acid as substrate,the Km and Vmax values of sPPO/mPPO were 205.896/205.067 mmol/L and 0.008/22.321 mmol·L^(-1)·min^(-1),respectively.Besides,the sodium sulfite and ascorbic acid could significantly restrain the activities of sPPO and mPPO,and phytic acid,oxalic acid,citric acid,and EDTA also showed different inhibitory degrees on sPPO and mPPO activities.These results demonstrated that the enzymatic properties of mPPO and sPPO presented great differences,mPPO showed obviously higher enzymatic activities than sPPO.Therefore,the effects of mPPO on enzymatic browning of black beauty potatoes should be emphasized during potatoes processing.

关 键 词：黑美人马铃薯 游离态多酚氧化酶 膜结合态多酚氧化酶 酶学性质 

分 类 号：S532[农业科学—作物学]