?莼菜中鋅蛋白的分離及初步分析?

?肖鶩軒 王昆侖 周海燕

摘 要：為了明確莼菜中鋅蛋白的分布及氨基酸組成，以富硒高鋅土壤中種植的莼菜為材料，對其幼葉蛋白質進行分離提取和分析。結果表明：莼菜中蛋白質主要類型為弱堿性蛋白質，比例為44.79%，但其鋅含量相對較低，水溶性蛋白比例只有15.43%，但其鋅含量卻是弱堿性蛋白質中的2.17倍，表明大部分鋅離子是與水溶性蛋白結合的;通過逐級鹽析從水溶性蛋白中獲得5個餾分，進一步分析各餾分的蛋白質含量及鋅含量，獲得WSⅡ和WSⅤ這2個高鋅含量的蛋白質餾分，電泳分析顯示這2個餾分分別由一個或一系列相同亞基組成;氨基酸組分分析顯示，WSⅡ和WSⅤ中甘氨酸、硒代半胱氨酸、組氨酸和賴氨酸含量較高。

關鍵詞：莼菜;鋅蛋白;分離;氨基酸組成

中圖分類號：Q513 文獻標識碼：A 文章編號：1006-060X（2020）04-0064-05

Preliminary Analysis and Separation of Zinc Protein in Brasenia schreberi

XIAO Wu-xuan1，WANG Kun-lun2，ZHOU Hai-yan2

（1. Hunan Institute of Nuclear Agriculture Science and Space Breeding， Hunan Academy of Agricultural Sciences， Changsha 410125， PRC;

2. College of Bioscience and Biotechnology， Hunan Agricultural University， Changsha 410128， PRC）

Abstract： Brasenia schreberi planted in selenium-rich and high-zinc soil was used as the target material in this study. The proteins in Brasenia schreberi young leaves were separated and analyzed for further clarification of zinc protein distribution and amino acid composition in the genus. The results show that the main type of proteins in Brasenia schreberi is weak alkaline protein， accounting for 44.79%， but its zinc content is relatively low; the proportion of water-soluble protein is only 15.43%， but its zinc content is 2.17 times that of weak alkaline protein， which indicates that most of the zinc ions are combined with water-soluble protein. Five fractions from water-soluble protein were obtained by stepwise salting out， then the protein content and zinc content of each fraction were analyzed， finally two protein fractions of high zinc content WSⅡ and WSⅤ were obtained. Electrophoresis analysis shows that these two fractions are composed of one or a series of the same subunits. Amino acid composition analysis shows that the contents of glycine， selenocysteine， histidine and lysine are high in WSⅡ and WSⅤ.

Key words： Brasenia schreberi; zinc protein; separation; amino acid composition

莼菜（Brasenia schreberi）又名蒪菜、馬蹄菜、湖菜等，系睡蓮目睡蓮科莼屬植物。莼菜為須根系植物，不定根簇生于地下匍匐莖的莖節(jié)靠近葉柄基部的兩側;莖可分為3類，分別是匍匐莖、縮短莖和水中莖[1];幼葉葉片呈現卷曲狀態(tài)，且葉外有透明質膠包裹，可食用[2];花由花瓣、花托、花萼、花梗及雌雄蕊組成，花期為2 d，第一天呈現雌蕊的功能，第二天則是展現雄花的功能，白天花朵浮出水面，主要靠風媒傳播授粉，夜晚花體沉入水中，于水中授粉結果，2～6周種子即可成熟[3]。莼菜在亞洲廣泛栽培，可有性繁殖，也可無性繁殖。

莼菜的營養(yǎng)價值較高，富含可溶性植物多糖、蛋白質及一些微量元素。目前已經檢測到的微量元素多達27種，其中鋅元素的含量遠超一般蔬菜[4]。……