DA201-C大孔吸附树脂对腐乳多肽脱盐作用的研究

为去除腐乳中的盐分,利于其中活性肽的分离纯化,以腐乳多肽的回收率为指标,采用DA201-C大孔吸附树脂对超滤的水溶性低聚肽的脱盐工艺进行了研究。结果表明:DA201-C大孔吸附树脂对腐乳多肽较佳的脱盐工艺条件为上样浓度45 mg/mL、洗脱流速120 mL/h、解吸剂为70%乙醇。腐乳多肽经DA201-C大孔吸附树脂处理后脱盐率达到98.19%,肽回收率大于90%,抗氧化活性得到提高。利用DA201-C大孔吸附树脂是进行腐乳多肽脱盐处理的一种简便有效方法。     

蚕蛹蛋白多肽液抗肿瘤作用的实验研究

通过动物及细胞实验研究蚕蛹蛋白多肽液的抗肿瘤作用。蚕蛹蛋白多肽质量浓度增加可使两肿瘤细胞存活率降低;肿瘤细胞总蛋白质含量随多肽浓度的增加逐渐降低(p<0.01),且在0.5～1.5g/L内呈剂量依赖性;对A549和Ketr-3的周期阻滞分别为G2～M期和G0～G1期;蚕蛹蛋白多肽液在150～600mg/g内,对小鼠S180和H22的抑瘤率分别达到28.72%～58.18%和27.64%～63.88%,明显延长EAC小鼠的生存时间。实验结果表明蚕蛹蛋白多肽液有显著的抗肿瘤作用。     

鹿茸多肽研究进展

鹿茸多肽占鹿茸总湿质量的50%～60%,是鹿茸中最为重要的生理活性物质之一。本文结合前人研究成果,综述鹿茸多肽的化学成分、提取方法和分离纯化方法,着重介绍鹿茸多肽对免疫系统、神经系统、心血管系统、骨骼系统的作用及其抗疲劳、抗氧化、抗肿瘤等生物活性,并对鹿茸多肽的发展趋势及研究前景进行展望。     

花生多肽的制备及纯化的研究

用AS1.398 中性蛋白酶水解花生蛋白得到花生多肽粗品,对影响花生蛋白水解的各种影响因素,如酶制剂的筛选,酶解工艺参数等进行了系统研究,得到最佳工艺条件为：pH6.7、反应温度50℃、酶解时间2.5h、加酶量为6500U/g 底物。超滤截取相对分子量小于5kD 和3kD 以下的两部分,冷冻干燥后用Sephadex G-25 柱层析分别得到两个和一个活性峰。在三甲基甘氨酸SDS- 聚丙烯酰胺凝胶电泳上显示单一条带的纯品。相对分子量分别在6.5kD 和 2kD 左右。     

FRACTIONATION OF SMALL PEPTIDES FROM BEER

Small peptides (MW<1000) were isolated from beer by hollow fibre ultrafiltration followed by column chromatography using the gel matrix Sephadex LH20. This simple procedure enabled the isolation of small peptides relatively free of other low molecular weight nitrogenous compounds. Analysis of the composition of subfractions from the small peptide fraction from pilot brewery beer and a commercial beer using reverse phase HPLC showed superior resolution of individual components compared to previously reported analytical techniques and demonstrated the presence of many peptide components. Acid hydrolysis and amino acid analysis of small peptide subfractions showed that the principal amino acid in each subfraction was glutamic acid/glutamine consistent with the release of peptides by proteolytic degradation of barley and malt proteins.     

Random Copolymers of Lysine and Isoleucine for Efficient mRNA Delivery

Messenger RNA (mRNA) is currently of great interest as a new category of therapeutic agent, which could be used for prevention or treatment of various diseases. For this mRNA requires effective delivery systems that will protect it from degradation, as well as allow cellular uptake and mRNA release. Random poly(lysine-co-isoleucine) polypeptides were synthesized and investigated as possible carriers for mRNA delivery. The polypeptides obtained under lysine:isoleucine monomer ratio equal to 80/20 were shown to give polyplexes with smaller size, positive ζ-potential and more than 90% encapsulation efficacy. The phase inversion method was proposed as best way for encapsulation of mRNA into polyplexes, which are based on obtained amphiphilic copolymers. These copolymers showed efficacy in protection of bound mRNA towards ribonuclease and lower toxicity as compared to lysine homopolymer. The poly(lysine-co-isoleucine) polypeptides showed greater than poly(ethyleneimine) efficacy as vectors for transfection of cells with green fluorescent protein and firefly luciferase encoding mRNAs. This allows us to consider obtained copolymers as promising candidates for mRNA delivery applications.     

γ-辐照生鲜猪肉中氨基酸及小分子肽组成特征分析

通过肽组学和氨基酸分析技术研究低剂量（3?kGy）辐照处理后,生鲜猪肉中各种肌肉蛋白质降解形成小分子肽的特征以及氨基酸组成,以期探索辐照对生鲜猪肉肌肉蛋白质降解的影响。结果表明,辐照处理后样品中亮氨酸（Leu）、异亮氨酸（Ile）、甲硫氨酸（Met）、谷氨酸（Glu）、丝氨酸（Ser）、苏氨酸（Thr）和半胱氨酸（Cys）含量比对照组显著降低（P＜0.05）,缬氨酸（Vla）、脯氨酸（Pro）2?种氨基酸与对照组差异不显著。不同肌肉蛋白质在辐照过程中的降解程度及对小分子肽形成的贡献不同。肌肉经辐照后共产生分子质量小于3?kDa的小分子肽104?种,其中肌原纤维蛋白辐照形成的小分子肽占50%以上。肌联蛋白、伴肌动蛋白、肌钙蛋白T和肌钙蛋白I降解形成的小分子肽占30.7%;肌间线蛋白、肌收缩蛋白和肌肉LIM结构域蛋白辐照形成小分子肽占22.2%。这些小分子肽的形成表明辐照会对肉品的滋味产生明显影响。     

多肽及蛋白质质谱分析新进展

多肽和蛋白质的结构分析常用化学及生物化学降解法，近年来运用质谱法日益增多，本文简要综述质谱新技术，如快原子轰击电离、串联质谱、电喷雾质等应用于多肽和蛋白质分子量测定及序列分析的新进展。     

EFFECTIVENESS OF THE ELECTROENDOSMOTIC PREPARATIVE ELECTROPHORESIS FOR THE PURIFICATION OF ALL PROTEINS AND POLYPEPTIDES FROM BEER

Ammonium sulphate precipitated beer proteins and polypeptides were fractionated by electroendosmotic preparative electrophoresis in the presence of sodium dodecyl sulphate. This one-step procedure allowed the contemporary purification of all beer proteins and polypeptides with molecular masses ranging from 6 up to 45 kDa. The obtained resolution was higher than that of any other technique, including analytical electrophoresis, since protein bands with minimal differences in molecular mass were collected pure in separated fractions. This procedure allows the recovery of purified beer components with minimal work, accordingly it can be considered a very useful tool for the preparation of fractions to be characterized and/or used for antibodies production.     

鮰鱼皮明胶ACE抑制肽降血压活性的研究

鮰鱼皮为斑点叉尾鮰鱼片加工的主要副产物,利用鮰鱼皮明胶制备降血压肽(ACE抑制肽)可为鮰鱼皮的高值化利用提供参考。本文通过对原发性高血压大鼠(SHR)进行一次性及长期给药(28 d)实验,研究鮰鱼皮明胶ACE抑制肽(Mr3000 Da)的降血压作用,并测定大鼠血清和肺组织中的ACE活性和Ang II含量。实验结果表明:一次性给药和长期灌胃给药鮰鱼皮明胶ACE抑制肽均对SHR大鼠有显著降血压作用,降血压效果呈剂量依赖性;高剂量组SHR大鼠灌胃给药2 h后,其收缩压由206 mmHg降至159 mmHg;高剂量组SHR大鼠经长期灌胃给药10 d后,血压一直保持在155 mmHg左右;同时,鮰鱼皮明胶ACE抑制肽对正常血压大鼠的降血压作用不显著。鮰鱼皮明胶ACE抑制肽对SHR大鼠血清和肺组织中的ACE活性有显著的抑制作用,从而使大鼠血清和肺组织中Ang II含量显著降低,而对正常血压的SD大鼠的血清和肺组织中ACE活性和Ang II含量影响不显著。