首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Gelatin extracted from Alaska pollack skin was hydrolyzed with serial digestions in the order of Alcalase, Pronase E, and collagenase using a three-step recycling membrane reactor. The fraction from the second step, which was hydrolyzed with Pronase E, was composed of peptides ranging from 1.5 to 4.5 kDa and showed high antioxidative activity. Two different peptides showing strong antioxidative activity were isolated from the hydrolysate using consecutive chromatographic methods including gel filtration on a Sephadex G-25 column, ion-exchange chromatography on a SP-Sephadex C-25 column, and high-performance liquid chromatography on an ODS column. The isolated peptides, P1 and P2, were composed of 13 and 16 amino acid residues, respectively; and both peptides contained a Gly residue at the C-terminus and the repeating motif Gly-Pro-Hyp. The antioxidative activities of the purified peptides were measured using the thiobarbituric acid method, and the cell viability was measured with MTT assay. The results showed that P2 had potent antioxidative activity on peroxidation of linoleic acid. Moreover, the cell viability of cultured liver cells was significantly enhanced by addition of the peptide. These results indicate that the purified peptide, P2, from gelatin hydrolysate of Alaska pollack skin is a natural antioxidant which has potent antioxidative activity.  相似文献   

2.
Angiotensin I-converting enzyme (ACE), a dipeptidyl carboxypeptidase, catalyzes the conversion of Angiotensin I to the potent vasoconstrictor Angiotensin II and plays an important physiological role in regulating blood pressure. Inhibitors of angiotensin 1-converting enzyme derived from food proteins are utilized for pharmaceuticals and physiologically functional foods. ACE inhibitory properties of different enzymatic hydrolysates of glycinin, the major storage protein of soybean, have been demonstrated. The IC50 value for the different enzyme digests ranges from 4.5 to 35 microg of N2. The Protease P hydrolysate contained the most potent suite of ACE inhibitory peptides. The ACE inhibitory activity of the Protease P hydrolysate after fractionation by RP-HPLC and ion-pair chromatography was ascribed to a single peptide. The peptide was homogeneous as evidenced by MALDI-TOF and identified to be a pentapeptide. The sequence was Val-Leu-Ile-Val-Pro. This peptide was synthesized using solid-phase FMOC chemistry. The IC50 for ACE inhibition was 1.69 +/- 0.17 microM. The synthetic peptide was a potent competitive inhibitor of ACE with a Ki of 4.5 +/- 0.25 x 10(-6) M. This peptide was resistant to digestion by proteases of the gastrointestinal tract. The antihypertensive property of this peptide derived from glycinin might find importance in the development of therapeutic functional foods.  相似文献   

3.
Angiotensin-I-converting enzyme (ACE) inhibitory activity was identified in milk proteins fermented with Lactobacillus (Lb.) helveticus NCC 2765 (Nestle Culture Collection, Vers-chez-les-Blanc, Switzerland). Hydrolyzing sodium caseinate for 1 and 2 h inhibited ACE activity, as measured by an in vitro ACE inhibition test. The hydrolysates with the highest ACE inhibitory potential were fractionated by gel permeation chromatography and their low molecular weight fractions collected. These fractions were subsequently subfractionated by reverse-phase high-pressure liquid chromatography. Several hydrophobic subfractions showed high ACE inhibitory potential, and their peptide composition was determined using an ion trap mass spectrometer equipped with an elctrospray ionization source. Analysis of the low molecular weight fraction identified 14 peptides with known antihypertensive activity and 1 with previously described opioid activity. On the basis of the peptide composition of active subfractions, two potentially active novel sequences were defined, and the following synthetic peptides were synthesized: FVAPFPEVFG (alphaS1 39-48), ENLLRFFVAPFPEVFG (alphaS1 33-48), NENLLRFFVAPFPEVFG (alphaS1 32-48), LNENLLRFFVAPFPEVFG (alphaS1 31-48), NLHLPLPLL (beta 147-155), ENLHLPLPLL (beta 146-155), and VENLHLPLPLL (beta 145-155). The ACE inhibitory potential of these synthetic peptides was assessed, and IC50 values were determined. NLHLPLPLL (beta 147-155), which was the only synthetic peptide also present in the sodium caseinate hydrolysates, and NENLLRFFVAPFPEVFG (alphaS1 32-48) showed the highest inhibition of ACE activity, with IC50 values of 15 and 55 microM, respectively. Furthermore, the stability of all synthetic peptides was assessed using an in vitro model simulating gastric digestion. The beta-casein-derived peptides remained intact following the successive hydrolysis by pepsin and pancreatin, whereas alphaS1-casein-derived peptides were degraded by pepsin.  相似文献   

4.
Bioprocesses were developed to enhance the value of proteins from deoiled corn germ. Proteins were hydrolyzed with trypsin, thermolysin, GC 106, or Flavourzyme to generate the bioactive peptide sequences. At an enzyme to substrate ratio of 1:100, protein hydrolysis of wet-milled germ was greatest using thermolysin followed by trypsin, GC 106, and Flavourzyme. For the dry-milled corn germ, protein hydrolysis was greatest for GC 106 and least for Flavourzyme. Electrophoretic patterns indicated that the hydrolysis conditions used were adequate for generating low molecular weight peptides for both germs. Unhydrolyzed dry- and wet-milled corn germ did not appear to contain angiotensin I converting enzyme (ACE)-inhibitory peptides. After hydrolysis with trypsin, thermolysin, and GC 106 but not Flavourzyme, ACE inhibition was observed. ACE inhibition was greatest for the GC 106 hydrolysate for both wet- and dry-milled corn germ. Denaturing the protein with urea before hydrolysis, in general, increased the amount of ACE-inhibitory peptides found in the hydrolysate. Membrane fractionations of both the wet- and dry-milled hydrolysates indicated that most of the ACE-inhibitory peptides were in the <1 kDa fraction. Examination of the control total protein extracts (before treatment with proteases) from wet- and dry-milled germ revealed that neither had ACE-inhibitory properties. However, when both total corn germ control protein extracts were fractionated, the <1 kDa fraction of wet-milled corn germ proteins exhibited ACE inhibition, whereas the comparable low molecular weight fraction from dry-milled corn germ did not.  相似文献   

5.
Angiotensin I converting enzyme (ACE) inhibitory peptide was isolated from tuna dark muscle hydrolysate prepared by alcalase, neutrase, pepsin, papain, alpha-chymotrypsin, and trypsin, respectively. Among hydrolysates, the pepsin-derived hydrolysate exhibited the highest ACE I inhibitory activity versus those of other enzyme hydrolysates. The structure of the peptide was identified to be Trp-Pro-Glu-Ala-Ala-Glu-Leu-Met-Met-Glu-Val-Asp-Pro (molecular weight 1581 Da) by time of flight mass spectrometry/mass spectrometry analysis, and the IC 50 value of the peptide was 21.6 microM. The Lineweaver-Burk plots revealed that the peptide acts as a noncompetitive inhibitor, and the inhibitor constant ( K i) was calculated as 26.6 microM using the secondary plots. The peptide had an antihypertensive effect according to the time-course measurement after oral administration to spontaneously hypertensive rats. Maximal reduction was detected 3 h after oral administration at a dose of 10 mg/kg of body weight. These results suggest that the peptide derived from tuna dark muscle would be a beneficial ingredient for functional food or pharmaceuticals against hypertension and its related diseases.  相似文献   

6.
To isolate and characterize novel angiotensin I-converting enzyme (ACE) inhibitory peptide from loach (Misgurnus anguillicaudatus), six proteases, pepsin, α-chymotrypsin, bromelain, papain, alcalase, and Neutrase, were used to hydrolyze loach protein. The hydrolysate (LPH) generated by bromelain [ratio of enzyme to substrate, 3:1000 (w/w)] was found to have the highest ACE inhibitory activity (IC(50), 613.2 ± 8.3 μg/mL). Therefore, it was treated by ultrafiltration to afford fraction of LPH-IV (MW < 2.5 kDa) with an IC(50) of 231.2 ± 3.8 μg/mL, having higher activity than the other fractions. Then, LPH-IV was isolated and purified by consecutive purification steps of gel filtration chromatography and reverse-phase high-performance liquid chromatography to afford a purified peptide with an IC(50) of 18.2 ± 0.9 μg/mL, an increase of 33.7-fold in ACE inhibitory activity as compared with that of LPH. The purified peptide was identified as Ala-His-Leu-Leu (452 Da) by Q-TOF mass spectrometry and amino acid analyzer. An antihypertensive effect in spontaneously hypertensive rats revealed that oral administration of LPH-IV could decrease systolic blood pressure significantly.  相似文献   

7.
Bovine skin gelatin was hydrolyzed with sequential protease treatments in the order of Alcalase, Pronase E, and collagenase using a three-step ultrafiltration membrane reactor. The molecular weight distributions of the first, second, and third hydrolysates were 4.8-6.6, 3.4-6.6, and 0.9-1.9 kDa, respectively. The angiotensin I converting enzyme (ACE) inhibitory activity of the third hydrolysate (IC(50) = 0.689 mg/mL) was higher than that of the first and second hydrolysates. Two different peptides showing strong ACE inhibitory activity were isolated from the hydrolysate using consecutive chromatographic methods including gel filtration chromatography, ion-exchange chromatography, and reversed-phase high-performance liquid chromatography. The isolated peptides were composed of Gly-Pro-Leu and Gly-Pro-Val and showed IC(50) values of 2.55 and 4.67 microM, respectively.  相似文献   

8.
为有效利用红娘鱼制备降血压肽,以红娘鱼鱼糜为原料提取蛋白,并对其进行酶解制备降血压肽。以血管紧张素转换酶ACE抑制率和水解度为指标,通过响应面分析法对酶解红娘鱼鱼糜蛋白制备降血压肽的工艺条件进行优化,并对最优条件下制备的酶解产物进行分子量和抗氧化活性测定。结果表明,碱性蛋白酶是制备降血压肽的最适蛋白酶,响应面法优化制备降血压肽的最佳酶解条件为pH值9、酶与底物的比值(酶底比)1.4%、温度54℃、时间2 h,此条件下酶解制得的降血压多肽ACE抑制率理论值为88%,实际值为89.3%;经高效液相色谱(HPLC)分析可得酶解产物相对分子量<2 000 Da。通过测定酶解产物样品的1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率、羟自由基(·OH)清除率及还原力判定其体外抗氧化活性,结果表明酶解产物具有较强抗氧化活性。本研究结果为红娘鱼的高值化利用提供了数据支持和理论基础。  相似文献   

9.
Soybean protein hydrolysates are widely used as functional foods as they have antioxidative properties able to enhance immune responses in humans. The alcalase enzymatic hydrolysates of beta-conglycinin were fractionated by ultrafiltration, and two main fractions, SP1 (<10 kDa) and SP2 (10-20 kDa), were obtained. The effects of these two fractions on the growth, development of epithelial cells, and formation of intercellular tight junctions were tested on an in vitro Caco-2 cell culture system. The inhibitory effects of SP1 and SP2 on the penetration of Salmonella typhimurium into Caco-2 epithelial cells were also examined. The results showed that the addition of >0.05 g/L of SP2 improved epithelial cell growth and that a concentration of 0.5 g/L of SP2 increased intercellular tight junction formation, which resulted in increased of transepithelial monolayer resistance (TER) values. Moreover, a lower S. typhimurium count compared to control was obtained when Caco-2 cells were grown in 0.05 and 0.5 g/L of SP2. These results show that beta-conglycinin hydrolysates play an important role in resisting S. typhimurium penetration into intestinal epithelial cells and that high molecular mass peptides (10-20 kDa) were more effective overall than low molecular mass peptides.  相似文献   

10.
A lung extract rich in angiotensin converting enzyme (ACE) and pure ACE were immobilized by reaction with the activated support 4 BCL glyoxyl-agarose. These immobilized ACE derivatives were used for purification of ACE inhibitory peptides by affinity chromatography. The immobilized lung extract was used to purify inhibitory peptides from sunflower and rapeseed protein hydrolysates that had been obtained by treatment of protein isolates with alcalase. The ACE binding peptides that were retained by the derivatives were specifically released by treatment with the ACE inhibitor captopril and further purified by reverse-phase C18 HPLC chromatography. Inhibitory peptides with IC50 50 and 150 times lower than those of the original sunflower and rapeseed hydrolysates, respectively, were obtained. The derivative prepared using pure ACE was used for purification of ACE inhibitory peptides from the same type of sunflower protein hydrolysate. ACE binding peptides were released from the ACE-agarose derivatives by treatment with 1 M NaCl and had an IC50 a little higher than those obtained using immobilized extract and elution with captopril. Affinity chromatography facilitated the purification of ACE inhibitory peptides and potentially other bioactive peptides present in food proteins.  相似文献   

11.
Sunflower protein isolates and the proteases pepsin and pancreatin were used for the production of protein hydrolysates that inhibit angiotensin-I converting enzyme (ACE). Hydrolysates obtained after 3 h of incubation with pepsin and 3 h with pancreatin were studied. An ACE inhibitory peptide with the sequence Phe-Val-Asn-Pro-Gln-Ala-Gly-Ser was obtained by G-50 gel filtration chromatography and high-performance liquid chromatography C18 reverse phase chromatography. This peptide corresponds to a fragment of helianthinin, the 11S globulin from sunflower seeds, which is the main storage protein in sunflower. These results show that sunflower seed proteins are a potential source of ACE inhibitory peptides when hydrolyzed with pepsin and pancreatin.  相似文献   

12.
Dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), was purified to homogeneity by DE-52 ion-exchange chromatography. This purified dioscorin was shown by spectrophotometric methods to inhibit angiotensin converting enzyme (ACE) in a dose-dependent manner (12.5-750 microg, respectively, 20.83-62.5% inhibitions) using N-[3-(2-furyl)acryloyl]-Phe-Gly-Gly (FAPGG) as substrates. The 50% inhibition (IC(50)) of ACE activity was 6.404 microM dioscorin (250 microg corresponding to 7.81 nmol) compared to that of 0.00781 microM (0.0095 nmol) for captopril. The commercial bovine serum albumin and casein (bovine milk) showed less ACE inhibitory activity. The use of qualitative TLC also showed dioscorin as ACE inhibitors. Dioscorin showed mixed noncompetitive inhibitions against ACE; when 31.25 microg of dioscorin (0.8 microM) was added, the apparent inhibition constant (K(i)) was 2.738 microM. Pepsin was used for dioscorin hydrolysis at 37 degrees C for different times. It was found that the ACE inhibitory activity was increased from 51.32% to about 75% during 32 h hydrolysis. The smaller peptides were increased with increasing pepsin hydrolytic times. Dioscorin and its hydrolysates might be a potential for hypertension control when people consume yam tuber.  相似文献   

13.
A soybean angiotensin I converting enzyme (ACE) inhibitory peptide fraction was reported to have antihypertensive activity in a rat study. The purpose of the present study was to examine if the presence of isoflavones in the soybean ACE inhibitory peptide fraction may contribute to the blood-pressure-lowering property. The isoflavone concentration in soybean samples was analyzed on a C 18 reverse-phase column using a two-step gradient solvent system. Producing soybean hydrolysate led to a nearly 40% loss of isoflavones compared with the original soybean flour, but the isoflavone composition did not change and the dominant isoflavone chemicals remained as 6'-O-malonylgenistin and 6'-O-malonyldaidzin. Ion exchange chromatography affected significantly both the content and the composition of the isoflavones. The dominant isoflavones in the ion-exchanged fraction were aglycones and nonacylated isoflavones, accounting for 95.8% of the total amount of 987.7 microg/g. It was calculated that the isoflavone content in the soybean ACE inhibitory peptide fraction was 25 times less than the minimal effective isoflavone dose reported. In vitro study also showed that adding isoflavones into both soybean flour hydrolysate and soybean ACE inhibitory peptide samples to a concentration of as high as 31.5% (w/w) did not affect ACE inhibitory activity (IC 50 values). The findings along with previously published results indicated that the contribution of isoflavones in soybean ACE inhibitory peptide fraction to the blood-pressure-lowering property in a short-term feeding study might be negligible.  相似文献   

14.
Fish protein hydrolysate (FPH) produced by incubation of Pacific hake fillet with 3.00% Protamex at pH 6.5 and 40 degrees C for 125 min demonstrated in vitro ACE-inhibitory activity (IC50 = 165 microg/mL), which was enhanced by ultrafiltration through a 10 kDa molecular weight cutoff membrane (IC50 = 44 microg/mL). However, after simulated gastrointestinal digestion, FPH and ultrafiltrate had similar ACE-inhibitory activity (IC 50 = 90 microg/mL), indicating that FPH peptides act as "pro-drug type" inhibitors and that enrichment by ultrafiltration may be unnecessary. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry confirmed that the molecular weights of major peaks were <1 kDa regardless of ultrafiltration. ACE-inhibitory activities of digested hydrolysates were not significantly affected by preincubation with ACE ( P > 0.05) and exhibited a competitive inhibitory mode. A permeability assay using fully differentiated colorectal adenocarcinoma (Caco-2) cells showed an apical to basolateral transport of peptides that ranged from approximately 2 to 20% after 2 h at 37 degrees C. Pacific hake fillet hydrolysates are a potentially bioavailable source of ACE-inhibitory peptides awaiting further in vivo study.  相似文献   

15.
Active compounds with antidiabetic potential were isolated from silk peptide E5K6 by consecutive ultrafiltration and gel filtration using Biogel P-2 and RS-HPLC using a YMC-Pack Pro C18 column. The highest α-glucosidase inhibitory activity of silk peptide E5K6 resulted from fractions with MW <1 kDa. The activities of gel-filtered fractions from silk peptide E5K6 of <1 kDa were assayed in vitro, demonstrating that the fourth peak (F4) had the highest α-glucosidase inhibitory activity (IC(50) = 37.1 mg/mL). F4 of silk peptide E5K6 was separated by HPLC into two peaks. Moreover, the purified compounds were identified as Gly-Glu-Tyr (GEY, MW = 367 Da) and Gly-Tyr-Gly (GYG, MW = 295 Da) according to amino acid sequences, and their α-glucosidase inhibitory activities (IC(50)) were 2.7 and 1.5 mg/mL, respectively.  相似文献   

16.
酶解制备鱼鳞蛋白降血压肽的工艺优化   总被引：1，自引：0，他引：1  
涂丹  张益奇  叶繁  戴志远 《核农学报》2019,33(1):120-128
为有效利用鱼鳞制备降血压肽,以罗非鱼鱼鳞为原料,在121℃条件下进行热预处理15 min后,运用响应面分析法优化酶解制备鱼鳞蛋白ACE抑制肽的工艺条件。结果表明,以水解度和ACE抑制率为评价指标,筛选出碱性蛋白酶为最优酶。在单因素试验的基础上,根据Box-Behnken中心组合试验设计原理,最终确立最优的酶解工艺参数为:酶解时间2 h、酶解温度56.3℃、pH值8.0,酶底比1.1%,此条件下ACE抑制率理论值为87.95%,实际值为88.26%。最优条件下制得的酶解产物相对分子质量集中在300～3 000 Da之间,水解效果较好。本研究结果对酶解法制备鱼鳞蛋白降血压活性肽具有一定的实践参考价值。  相似文献   

17.
The in vitro angiotensin I-converting enyzme (ACE) inhibitory activity of Pacific hake hydrolysates was investigated as a function of hydrolysis conditions, starting material variability, and ultrafiltration. Hake fillets were hydrolyzed using Protamex protease under various conditions of pH, hydrolysis time, and enzyme-to-substrate ratio (% E/S) according to a response surface methodology (RSM) central composite design. The hydrolysate produced at pH 6.5, 125 min, and 3.0% E/S had an IC 50 of 165 +/- 9 microg of total solids/mL. ACE-inhibitory activity was not significantly different (P < 0.05) for hydrolysates produced using higher time-enzyme combinations within the model or from fish of different catches. Ultrafiltration (10 kDa molecular mass cutoff) resulted in an IC50 value of 44 +/- 7 microg of peptides/mL, 2.5 times more potent than the commercial product PeptACE Peptides (IC50 = 114 +/- 8 microg of peptides/mL). These results suggest that hydrolysates prepared with minimal fractionation from Pacific hake, an undervalued fish, may be a commercially competitive source of ACE-inhibitory peptides.  相似文献   

18.
Loach protein hydrolysates (LPH) prepared by papain digestion were fractionated into four fractions, LPH-I (MW > 10 kDa), LPH-II (MW = 5-10 kDa), LPH-III (MW = 3-5 kDa), LPH-IV (MW < 3 kDa), and the in vitro antioxidant and antiproliferative (anticancer) activities of all fractions were determined. LPH-IV showed the lowest IC(50) value (16.9 ± 0.21 mg/mL) for hydroxyl radical scavenging activity and the highest oxygen radical scavenging capacity (ORAC) value (reaching 215 ± 5.9 mM Trolox/100 g loach peptide when the concentration was 60 μg/mL). Compared with other fractions, LPH-IV also exhibited stronger antiproliferative activity for human liver (HepG2), breast (MCF-7), and colon (Caco-2) cancer cell lines in a dose-dependent manner. When the protein concentration was 40 mg/mL, the HepG2 and MCF-7 cell proliferation of LPH-IV reached 7 and 4%, respectively, with no significant difference from those of LPH (8 and 7%, p > 0.05), with significantly less growth than those of LPH-I, LPH-II, and LPH-III, respectively (p < 0.05). The Caco-2 colon cell proliferation of LPH-IV was 12.8- and 8.7-fold smaller than those of LPH-I and LPH-II, respectively (p < 0.05). All of the fractions had a greater ability to inhibit Caco-2 colon cancer cell proliferation than to inhibit HepG2 liver cancer and MCF-7 breast cancer cell proliferation. The ORAC values of most of the fractions correlated (R(2) > 0.86, p < 0.01) with the antiproliferative activity of the three cancer cell lines, suggesting that higher antioxidant activity leads to better antiproliferative activity. However, further mechanistic and human clinical studies of the anticancer activity of loach protein hydrolysate fractions are needed.  相似文献   

19.
Gastrointestinal digestion is of major importance in the bioavailability of angiotensin I converting enzyme (ACE) inhibitory peptides, bioactive peptides with possible antihypertensive effects. In this study, the conditions of in vitro gastrointestinal digestion leading to the formation and degradation of ACE inhibitory peptides were investigated for pea and whey protein. In batch experiments, the digestion simulating the physiological conditions sufficed to achieve the highest ACE inhibitory activity, with IC(50) values of 0.076 mg/mL for pea and 0.048 mg/mL for whey protein. The degree of proteolysis did not correlate with the ACE inhibitory activity and was always higher for pea than whey. In a semicontinuous model of gastrointestinal digestion, response surface methodology studied the influence of temperature and incubation time in both the stomach and small intestine phases on the ACE inhibitory activity and degree of proteolysis. For pea protein, a linear model for the degree of proteolysis and a quadratic model for the ACE inhibitory activity could be constituted. Within the model, a maximal degree of proteolysis was observed at the highest temperature and the longest incubation time in the small intestine phase, while maximal ACE inhibitory activity was obtained at the longest incubation times in the stomach and small intestine phase. These results show that ACE inhibitory activity of pea and whey hydrolysates can be controlled by the conditions of in vitro gastrointestinal digestion.  相似文献   

20.
It has been reported that soybean peptide fractions isolated from Korean fermented soybean paste exert angiotensin I converting enzyme (ACE) inhibitory activity in vitro. In this study, further purification and identification of the most active fraction inhibiting ACE activity were performed, and its antihypertensive activity in vivo was confirmed. Subsequently, a novel ACE inhibitory peptide was isolated by preparative HPLC. The amino acid sequence of the isolated peptide was identified as His-His-Leu (HHL) by Edman degradation. The IC(50) value of the HHL for ACE activity was 2.2 microg/mL in vitro. Moreover, the synthetic tripeptide HHL (spHHL) resulted in a significant decrease of ACE activity in the aorta and led to lowered systolic blood pressure (SBP) in spontaneously hypertensive (SH) rats compared to control. Triple injections of spHHL, 5 mg/kg of body weight/injection resulted in a significant decrease of SBP by 61 mmHg (p < 0.01) after the third injection. These results demonstrated that the ACE inhibitory peptide HHL derived from Korean fermented soybean paste exerted antihypertensive activity in vivo.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号