汉麻降脂肽氨基酸序列分析

Analysis on Amino Acid Sequence of Hemp Seed Hypolipidemic Polypeptide

采用糠醛显色法,以汉麻籽多肽体外结合胆酸盐的能力作为判断降血脂效果的指标,通过对不同分子质量多肽结合胆酸盐能力的对比分析,筛选出降血脂最强的多肽组分。采用基质辅助激光解析飞行时间质谱仪(MALDI-TOF)对降血脂最强的多肽组分进行分子质量分布测定。采用液相色谱-串联质谱(LC-MS/MS)技术对多肽降血脂最强的组分进行氨基酸序列分析。结果表明,不同分子质量的汉麻籽多肽各组分对3种胆酸盐都具有一定的吸附作用,其中以组分H4(<1 ku)对胆酸盐的吸附能力最强。对组分H4中丰度较高的5个肽段815.4、733.4、655.3、574.3、513.2 u进行序列测定,其氨基酸序列分别为NNGDSPLV、MLPLLF、ELAPLL、SLLEL、LSFF。5个序列中均含有疏水性氨基酸亮氨酸,而且5个氨基酸序列末端的氨基酸均是疏水性氨基酸缬氨酸、亮氨酸和苯丙氨酸。汉麻籽多肽具有一定的降血脂作用,通过氨基酸组成与序列分析,推断汉麻籽多肽降血脂活性与其分子质量大小及疏水性氨基酸有关。

The ability of hemp seed polypeptide to combine with cholic acid salt in vitro was used as the parameter to judge the effect of reducing blood lipid by furfural coloration.Through the comparative analysis of the ability of different molecular weight polypeptide to combine with cholic acid salt,the most effective polypeptide component was selected.MALDI-TOF was used to determine the molecular weight distribution of the most effective peptide components.LC-MS/MS was used to analyze the amino acid composition and sequence of the most effective component of polypeptide.The results showed that each component of hemp seed polypeptide with different molecular weight had certain adsorption effect on all three different kinds of cholate,among which H4(<1 ku)had the strongest adsorption effective on cholate.The amino acid sequences of peptide fragments that molecular weight were 815.4、733.4、655.3、574.3 u and 513.2 u,which were higher in H4,were determined.The sequences were NNGDSPLV、MLPLLF、ELAPLL、SLLEL、LSFF,respectively.Hydrophobic amino acids(Leucine)were found in the five fragments,and the amino acids at the end of the five amino acid sequences were all hydrophobic amino acids(Valine,Leucine,and Phenylalanine).Through amino acid composition and sequence analysis,it was concluded that the antilipidemic activity of hempseed polypeptide was related to its molecular weight and hydrophobic amino acid rate.