大孔吸附树脂分离魔芋飞粉中ACE抑制肽工艺研究

采用大孔吸附树脂对魔芋ACE抑制肽进行分离,比较3种大孔吸附树脂对魔芋飞粉中ACE抑制肽的静态吸附和解吸效果,从中筛选出适合该魔芋ACE抑制肽分离纯化的树脂。结果表明,DA201-C型树脂最适合魔芋飞粉中ACE抑制肽的纯化。通过对影响树脂吸附解吸的各种因素进行系统地研究,确定工艺参数。最佳工艺参数为上样浓度8 mg/mL、pH 2.0、上样量8 mL、洗脱液乙醇体积分数80%、洗脱流速1.0 mL/min、洗脱时间2 h,在此条件下,分离得到的魔芋ACE抑制肽的抑制率为95.19%。     

鱼降压肽的大孔吸附树脂分离及其活性稳定性

采用大孔吸附树脂对碱性蛋白酶水解、水解度为34.52% 的鱼降压肽进行分离。结果表明,DA201-C 型大孔吸附树脂对鱼降压肽吸附性最好,乙醇体积分数为75% 时洗脱下来的组分具有最高的ACE 抑制活性,其IC50为1.52mg/ml。鱼降压肽中灰分由分离前的9.47% 减少到分离后的2.34%,肽和蛋白质含量分别由分离前的72.81%和81.26% 增加到分离后的80.24% 和92.42%。活性稳定性分析显示,胃蛋白酶和胰酶、中性和低酸性pH 值、55℃以下温度以及1000mmol/L 以内的NaCl 浓度对鱼降压肽的ACE 抑制活性影响较小。     

大孔树脂吸附分离蚕蛹ACE抑制肽的研究

为了找出大孔树脂纯化蚕蛹ACE抑制肽的方法。比较了5种大孔树脂在纯化蚕蛹ACE抑制肽时的吸附率和解吸率,得出DA201-C分离蚕蛹ACE抑制肽的效果最好。再进一步考察上样流速、上样浓度、分级洗脱等对DA201-C大孔树脂吸附及分离效果的影响。最终结果为75%乙醇洗脱下的多肽的ACE抑制率最高,其IC50为0.632mg/mL,并且发现疏水性与ACE抑制率呈正相关。     

响应面法优化大孔树脂吸附发酵羊乳ACE抑制肽

血管紧张素转换酶(ACE)的活性过高是导致高血压的重要因素之一。ACE抑制肽可有效地抑制ACE的活性。为了制备高纯度的ACE抑制肽,考查不同截留分子量超滤膜对发酵羊乳中的ACE抑制肽的分离效果,比较4种树脂(AB-8、HPD-100、DA201-C、DM130)对ACE抑制肽的纯化效果,选择最佳树脂并对其纯化工艺参数进行优化。结果表明,经超滤分离后,ACE抑制肽主要集中在M1 ku组分中,其IC50值降到了0.348 mg/mL,ACE抑制率为86.91%,比超滤前ACE抑制率提高了5.61%;大孔树脂DA201-C最佳,静态吸附最佳工艺条件为上样pH2.15、上样浓度20 mg/mL、吸附率为(72.38±1.26)%,通过大孔树脂后IC_(50)值达到0.301 mg/mL,与超滤液相比IC50降低了0.047 mg/mL。     

苋籽ACE抑制肽的大孔树脂分离纯化

比较6种大孔树脂对苋籽ACE抑制肽的吸附-解吸效果,从中筛选出合适该活性肽分离纯化的树脂,并对其吸附-解吸工艺进行优化.结果表明,DA201-C树脂最适合苋籽ACE抑制肽的纯化,在样品质量浓度10mg/mL,pH为5,上样量1BV,流速6mL/min时,树脂的吸附效果最佳,吸附率达83.69％,再用5BV体积分数75％乙醇,以5mL/min的流速进行洗脱,此时几乎把吸附的多肽全部洗脱下来,解吸率为98.69％.经树脂纯化,样品的蛋白纯度为89.47％,脱盐率为88.86％,短肽含量提高了20.96％,ACE抑制活性提高了27.91％.     

大豆肽的离子交换色谱分离及其活性评价

采用Sephadex C-25阳离子交换剂对经过DA201-C型大孔吸附树脂脱盐、乙醇梯度洗脱(75%乙醇洗脱组分)的Alcalase水解大豆肽(DH14%)进行进一步的分离纯化,并对分离得到的各组分ACE抑制活性进行了评价。试管试验确定的SephadexC-25色谱分离条件为:上样量0.004g/mLIE,起始缓冲液为1M醋酸,上样吸附率为61.19%。经SP-Sephadex C-25分离得到6个组分,其中未吸附的3个组分ACE抑制活性低,但NaCl梯度洗脱的3个组分ACE活性均为60%左右,从纯化ACE抑制活性肽的角度考虑,分离效果比SephadexG-15差。     

大孔吸附树脂分离纯化海蜇ACE抑制肽的工艺研究

本文主要从分子极性角度研究了大孔吸附树脂对具有血管紧张素转化酶(Angiotensin-I converting enzyme,ACE)抑制活性的海蜇多肽的分离纯化作用.取海蜇酶解产物作为研究对象,选用HP20SS、SP20SS、SP207三种不同型号的大孔吸附树脂分离纯化海蜇ACE抑制肽,以ACE抑制率为评价指标,对...     

燕麦ACE 抑制肽的分离纯化及其活性研究

通过对3 种大孔吸附树脂的比较,选择DA201-C 树脂对燕麦ACE 抑制肽进行纯化。纯化后的燕麦肽产物的ACE 抑制率达到92.86%,利用HPLC 测得纯化后燕麦ACE 抑制肽的分子质量分布在240.10～1292.11D 之间,这部分物质在整个纯化产物中占99.82%。采用SephadexG-15 凝胶分离燕麦ACE 抑制肽得到D峰,其IC50 为0.103mg/mL,分子质量545D。采用大孔吸附树脂及凝胶层析法能够较好地分离纯化燕麦ACE 抑制肽。     

大孔吸附树脂对麦胚肽的吸附特性研究

从大孔吸附树脂对麦胚肽的静态吸附率与解吸率考察了9种树脂的吸附性能，DA201—C大孔吸附树脂吸附特性优于其它8种树脂；吸附流速、麦胚肽的浓度及不同离子强度的样品溶液等对大孔吸附树脂动态吸附性能有影响；DA201-C大孔吸附树脂对麦胚肽的脱盐率为92．13％，麦胚肽的回收率为78．55％：利用不同浓度乙醇可将麦胚肽段按疏水性大小进行初步分离纯化，具有最大疏水性值的75％乙醇洗脱组分清除超氧阴离子自由基（听）的能力最强，其IC50为490．49μg/mL。     

大孔吸附树脂吸附分离高活性玉米抗氧化肽

采用大孔吸附树脂对玉米抗氧化肽进行分离,通过单因素试验得出XAD-7HP树脂为最适树脂,在此基础上,研究不同pH值条件下的静态吸附能力和不同解吸剂的静态解吸能力等实验,确定玉米抗氧化肽吸附分离的基本参数为pH7.0、解吸剂体积分数70%。通过动态吸附分离实验得出,该树脂可以达到分离纯化玉米抗氧化肽的目的,而且分离后的玉米肽的抗氧化活性比原液提高了1倍。     

酶解脱脂蚕蛹蛋白制备ACE抑制肽

以实验室自制的脱脂蚕蛹蛋白为原料,利用酶工程技术,通过对中性蛋白酶、碱性蛋白酶、木瓜蛋白酶、复合蛋白酶、风味蛋白酶、胰蛋白酶等的筛选及单因素和响应面优化试验,对ACE抑制肽的制备工艺条件进行较系统的研究。结果表明：选择碱性蛋白酶作为脱脂蚕蛹蛋白制备ACE抑制肽的酶,制备ACE抑制肽的最佳工艺条件为料液比11.88:100、温度50.22℃、pH 9.46、加酶量7.03%、酶解4h。在此条件下制备的ACE抑制肽的ACE抑制率达到41.98%。     

Purification and identification of an ACE-inhibitory peptide from walnut protein hydrolysate

Angiotensin I-converting enzyme (ACE) is a dipeptidyl carboxypeptidase. It plays an important physiological role in regulating blood pressure in human bodies. ACE-inhibitory peptides inhibit the activity of ACE, thereby decreasing the tension of blood vessels and the blood volume, thus lowering blood pressure. ACE-inhibitory peptides derived from food proteins due to their safety properties and beneficial effects on human health have attracted more and more attentions on their ACE-inhibitory activity. In the present study, a novel ACE-inhibitory peptide, P-1a1, was homogeneously purified from walnut protein hydrolysate by ultrafiltration, consecutive column chromatography and high performance liquid chromatography. The purified peptide was characterized by Edman degradation, matrix-assisted laser desorption ionization time-of-flight mass spectrophotometer and a liquid-phase peptide sequencer. The amino acid sequence of P-1a1 was determined to be LPGRPPIKPWPL. The potent ACE-inhibitory peptide showed a high ACE-inhibitory activity with the IC₅₀ value of 128.98 μg/mL (95.2 μmol/L). The purified peptide could be used in functional food products as a bioactive component with good ACE-inhibitory activity.     

Angiotensin I-converting enzyme-inhibitory peptide fractions from albumin 1 and globulin as obtained of amaranth grain

A number of biopeptides promoting health benefits have been isolated from food-protein hydrolysates and can be released during enzymatic digestion. Antihypertensive peptides can be part of protein fractions from amaranth grain. The objective of this work was to obtain ACE-inhibitory peptide fractions from albumin 1 and the globulin of amaranth (Amaranthus hypochondriacus) grain. Albumin 1 and globulin were hydrolysed with alcalase; hydrolysis was monitored by proteolytic degradation and by ACE-inhibitory activity. The highest ACE-inhibitory activity was 40% and 35% as obtained after 18 and 15 h hydrolysis for albumin 1 and globulin, respectively. Further separation and purification of the ACE-inhibitory peptide fractions were carried out by gel filtration and C₁₈ RP–HPLC. The IC₅₀ was 0.35 ± 0.02 mg/ml for albumin 1 peptide fraction and 0.15 ± 0.03 mg/ml for globulin peptide fraction. Albumin 1 peptide fraction showed an competitive mode of ACE inhibition, whereas the globulin peptide fraction was competitive. The globulin peptide fraction may have one of the most active naturally-occurring ACE-inhibitory peptides.     

Effect of simulated gastrointestinal digestion on the antihypertensive properties of synthetic beta-lactoglobulin peptide sequences

In this study, the antihypertensive activity in spontaneously hypertensive rats of two peptides isolated from beta-lactoglobulin hydrolysates with thermolysin was evaluated. These peptides, with sequences LLF [beta-lg f(103-105)] and LQKW [beta-lg f(58-61)], showed potent in vitro ACE-inhibitory activity. Two hours after administration, both sequences caused a clear and significant decrease in the blood pressure of these rats. The impact of a simulated gastrointestinal digestion on ACE-inhibitory and antihypertensive activities of these peptides was also studied. The results showed that both fragments were susceptible to proteolytic degradation after incubation with pepsin and Corolase PP. In addition, their in vitro ACE-inhibitory activity decreased after the simulated digestion. It is likely that fragment LQK was the active end product of the gastrointestinal digestion of peptide LQKW. The fragment LL, observed after digestion of peptide LLF, probably exert its antihypertensive effect through a mechanism of action different than ACE-inhibition.     

干酪乳杆菌LC-15发酵乳血管紧张素转换酶体外抑制活性的研究

血管紧张素转换酶抑制剂筛选模型是一个用于抗高血压药物和功能性食品研究的有效模型。通过考察乳酸菌蛋白质水解能力与ACE抑制活性的关系，以一株具有较高ACE抑制活性的干酪乳杆菌LC-15为研究对象，研究了发酵时间、添加酪蛋白、酶水解处理和模拟胃肠消化对LC-15发酵乳的ACE抑制活性的影响。结果表明，乳酸菌对牛乳蛋白质的水解能力与ACE抑制活性呈现一定的正相关关系；干酪乳杆菌LC-15在复原脱脂乳中发酵至42h时，发酵乳的ACE抑制活性达到最高，此时ACE抑制率为66％；通过在复原脱脂乳中添加4％酪蛋白可以使LC-15发酵乳的ACE抑制活性提高到81％；控制复原脱脂乳水解度为10％，然后再利用LC-15进行发酵得到的发酵乳的ACE抑制活性达到85％；在模拟胃肠环境消化条件下LC-15发酵乳的ACE抑制活力从最初的85％下降到78％。     

Angiotensin converting enzyme-inhibitory activity of peptides isolated from Manchego cheese. Stability under simulated gastrointestinal digestion

In this study, several peptides, which had previously been identified in active HPLC fractions from Manchego cheese, were synthesised and their angiotensin converting enzyme (ACE)-inhibitory activities were measured. From 11 peptides, which were selected based on their structures, only two, VRYL and KKYNVPQL, showed considerable ACE-inhibitory activity with IC₅₀ values of 24.1 and 77.1 μ , respectively. Subsequently, the impact of the gastrointestinal digestion on ACE-inhibitory activity was evaluated. Some of the peptides selected were resistant to the incubation with pepsin followed by hydrolysis with a pancreatic extract. The ACE-inhibitory activity after simulated digestion did not change drastically except for peptide _s2-CN f(195-204) (TQPKTNAIPY) that exhibited an activity 6 times greater after simulated digestion. In contrast, after simulated digestion, the activities of peptides VRYL and KKYNVPQL decreased. The peptides not hydrolysed by gastrointestinal enzymes and peptide VRYL, which was only partly hydrolysed, were incubated with ACE and were found to be true inhibitors of the enzyme and to have a competitive inhibition pattern.     

Angiotensin-converting enzyme inhibitory activity of peptides derived from caprine kefir

In this study, a potent angiotensin-converting enzyme (ACE)-inhibitory activity was found in a commercial kefir made from caprine milk. The low molecular mass peptides released from caseins during fermentation were mainly responsible for this activity. Sixteen peptides were identified by HPLC-tandem mass spectrometry. Two of these peptides, with sequences PYVRYL and LVYPFTGPIPN, showed potent ACE-inhibitory properties. The impact of gastrointestinal digestion on ACE-inhibitory activity of kefir peptides was also evaluated. Some of these peptides were resistant to the incubation with pepsin followed by hydrolysis with Corolase PP. The ACE-inhibitory activity after simulated digestion was similar to or slightly lower than unhydrolyzed peptides, except for peptide β-casein f(47-52) (DKIHPF), which exhibited an activity 8 times greater after hydrolysis.     

Contribution of Leu and Hyp residues to antioxidant and ACE-inhibitory activities of peptide sequences isolated from squid gelatin hydrolysate

Squid gelatin obtained from inner and outer tunics was hydrolysed with Alcalase to isolate antioxidant peptide sequences. The ACE-inhibitory activity of the isolated peptides was also evaluated. After fractionation by ultrafiltration and size-exclusion chromatography into four fractions, the antioxidant activity of the peptide fractions was determined by radical scavenging ability and ferric reducing power. Fraction FIII showed the highest antioxidant activity, although slight differences could be expected in the antioxidant activity of the different fractions based on the amino acid composition. FIII was subjected to liquid chromatography and tandem mass spectrometry (LC–MS/MS) and two major compounds were identified: the compound with m/z 952.42, which could be mostly comprised by the carbohydrate fucose, and the peptide with m/z 1410.63. Three possible sequences were proposed and synthesised for this peptide, and the contribution of Leu or Hyp residues to the antioxidant and ACE-inhibitory activities of the resulting sequence was evaluated. The presence of Leu residues in the peptide sequence in replacement of Hyp seems to play an important role in the antioxidant and ACE-inhibitory activity.     

鲢鱼蛋白制备ACE抑制肽的工艺优化

研究制备鲢鱼蛋白ACE抑制肽工艺条件,利用高效液相色谱法测定不同蛋白酶水解鲢鱼蛋白的ACE抑制率,筛选出风味蛋白酶为最佳酶源。在单因素试验的基础上,采用Box-Beknken中心组合设计建立响应面数学模型。得出鲢鱼蛋白制备ACE抑制肽的最佳工艺条件为初始pH 7.54,酶解温度50.56℃,时间4.5h,加水量46.67mL/10g.鱼肉。经优化后,鲢鱼蛋白ACE抑制肽的抑制率实际值可达81.35%。     

Angiotensin I converting enzyme-inhibitory activity of bovine, ovine, and caprine kappa-casein macropeptides and their tryptic hydrolysates

This work evaluated the angiotensin-converting enzyme (ACE)-inhibitory activities of bovine, ovine, and caprine kappa-casein macropeptides (CMPs) and their tryptic hydrolysates. The results obtained indicate that bovine, ovine, and caprine CMPs exhibited moderate in vitro ACE-inhibitory activities that increased considerably after digestion under simulated gastrointestinal conditions. Active peptides could also be produced from CMPs via proteolysis with trypsin, with tryptic hydrolysates exhibiting a more extensive ACE-inhibitory activity than intact CMPs during simulated gastrointestinal digestion. Two active fractions were chromatographically separated from the tryptic hydrolysate of the bovine CMP, but their complexity hampered the assignment of the ACE-inhibitory activity to specific peptide sequences. Evidence for the release of the strong ACE-inhibitory tripeptide IPP was found upon simulation of the gastrointestinal digestion of peptides released by trypsin from the CMP sequence. These findings might help to promote further exploitation of cheese whey in the preparation of nutraceuticals for inclusion in the composition of functional food products with high added values.