热处理对参与西兰花叶绿素降解的过氧化物同工酶活性的影响  

Effects of Heat Treatment on Isoperoxidases Activity in Chlorophyll Degradation of Broccoli

作　　者：柴薇薇[1] 冯玉兰[1] Cai Weiwei;Feng Yulan(College of Life Science and Engineering,Northwest University for Nationalities,Lanzhou,730030)

机构地区：[1]西北民族大学生命科学与工程学院

出　　处：《基因组学与应用生物学》2019年第11期5120-5124,共5页Genomics and Applied Biology

基　　金：西北民族大学“一优三特”学科中央高校基本科研业务费专项资金项目(31920180132);兰州市科技局项目(2015-3-112)共同资助

摘　　要：为了揭示热处理对参与西兰花(Brassica oleracea L.)叶绿素降解的过氧化物同工酶活性的影响,通过分子排阻色谱法检测涉及叶绿素(Chl)降解的3种过氧化物同工酶Ⅰ型、Ⅱ型和Ⅲ型的变化,同时讨论热处理和放线菌酮对酶活性的影响。结果显示,未经热处理的西兰花小花的叶绿素a和叶绿素b含量在16℃下2d后显著下降,而经热处理的小花中的含量(50℃下1.5h)几乎没有变化。新鲜西兰花小花中可检测到Ⅰ型,并且其在未经热处理的西兰花中的活性随着储存时间显著增加。而热处理抑制了所有异构过氧化物酶活性的增强。放线菌酮处理也有效地阻止Ⅰ、Ⅱ和Ⅲ类过氧化物酶活性的增加,同时抑制小花变黄。与Ⅰ型相比,Ⅱ型和Ⅲ型在Chl a上表现出更低的Km和更高的Vmax/Km值。这表明Ⅱ型和Ⅲ型都可能与西兰花小花中的Chl降解密切相关,并且热处理可能通过抑制异构过氧化物酶活性来抑制小花衰老。In order to reveal the effect of heat treatment on the activity of isoperoxidases involved in chlorophyll degradation of broccoli(Brassica oleracea L.),the changes of three isoperoxidases(TypeⅠ,ⅡandⅢ)were involved in the degradation of chlorophyll(Chl)by size exclusion chromatography.The effects of heat treatment and cycloheximide on enzyme activity were also discussed.The results showed that the content of chlorophyll a and b of broccoli floret without heat treatment decreased significantly after 2 days at 16℃,while the content of heat-treated floret(1.5 h at 50℃)had almost no change.TypeⅠwas detected in fresh broccoli florets and its activity in non-heat treated broccoli increased significantly with storage time.The heat treatment inhibited the enhancement of all isoperoxidase activities.The cycloheximide treatment also effectively prevented the increase of the isoperoxidase activity of TypesⅠ,ⅡandⅢ,and inhibited the yellowing of the floret.Compared with TypeⅠ,TypeⅡand TypeⅢexhibited lower Km and higher Vmax/Km values on Chl a.This indicates that both TypeⅡand typeⅢmay be closely related to degradation of Chl in broccoli floret,and heat treatment may inhibit floret senescence by inhibiting isoperoxidase activity.

关 键 词：西兰花 热处理 过氧化物同工酶 叶绿素降解 放线菌酮 

分 类 号：S635.3[农业科学—蔬菜学]