聚合草叶蛋白提取方法比较及氨基酸组成分析

Comparison of Different Extraction Methods for SympHytum pezegrinum L.Leaf Protein and Analysis of Amino Acid Composition

目的对聚合草叶蛋白提取率进行比较及氨基酸组分分析与评分。方法用TCA-丙酮沉淀法、SDS法、酚法对干叶和鲜叶中粗蛋白进行提取,计算蛋白提取物的纯度;按照GB/T 5009.124-2003方法进行氨基酸组分分析,按FAO方法进行氨基酸评分,并用Pensflorida方法测定EAAI。结果酚法提取聚合草叶片总蛋白的得率最高(鲜叶84.7%、干叶62.51%),SDS法次之(湿叶70.06%、干叶55.67%),TCA-丙酮沉淀法最差(湿叶51.76%,干叶46.45%),且酚法蛋白提取物的纯度较高(鲜叶64.4%、干叶51.46%)。经氨基酸组分分析得知聚合草叶蛋白中必需氨基酸含量由高到低依次为:亮氨酸(1.72)、缬氨酸(1.16)、赖氨酸(1.09)、苯丙氨酸(1.01)、苏氨酸(0.94)、异亮氨酸(0.79)、色氨酸(0.28)、蛋氨酸(0.21)。结论鲜叶中粗蛋白得率较高,蛋白提取率及提取蛋白的纯度酚法均最高。

Objective To compare the extraction rate of three different methods used to extracted protein both from dried leaves and fresh leaves.Methods Leave crude protein was extracted by TCA-acetone precipitation,SDS method and phenol method respectively.According to GB/T 5009.124-2003 method using amino acid analyzer for analysis of amino acid composition,amino acid score method according to FAO,and with Pensflorida determined EAAI.Results SDS method followed(70.06%wet leaves,dry leaves 55.67%),TCA-acetone precipitation worst(wet leaves 51.76%,46.45%dry leaf),and phenol extraction of high purity(64.4%of fresh leaves,dry leaves 51.46%).The amino acid composition analysis showed that the amino acids contained in protein SympHytum pezegrinum L.species up to 18 species,of which the full range of essential amino acids,accounting for 40.37%by weight amino acids,and its content(g/100g)in order were:leucine(1.72),valine(1.16),lysine(1.09),phenylalanine(1.01),threonine(0.94),isoleucine(0.79),tryptophan(0.28),methionine(0.21).Conclusion The extraction rate from fresh leaf was higher t,phenol method had the highest extraction rate and the resulted protein showed the highest purity.