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1.
本实验采用超滤法分离发酵乳中的ACE抑制肽,研究了超滤工艺的主要技术参数.给果表明:截留分子量为5000Da的超滤膜,在压力0.1OMPe,温度37℃条件下.能得到具有较高ACE抑制活性的超滤液.  相似文献   

2.
以扇贝裙边的酶解产物——蛋白多肽对ACE活性的抑制率作为控制水解程度的指标,确定制备ACE活性抑制肽的最佳酶种及酶解工艺技术条件.通过胰蛋白酶、胃蛋白酶、木瓜蛋白酶、复合风味酶、枯草杆菌蛋白酶5种酶酶解扇贝裙边得到的蛋白多肽对ACE抑制能力的比较发现,5种酶在不同酶解时间所得到的酶解蛋白多肽都具有一定的ACE抑制能力,其中胃蛋白酶酶解蛋白多肽的ACE抑制率最高,为91.33%;再经L9(3)4正交实验对胃蛋白酶酶解工艺条件进行优化,确定酶解反应最佳条件是酶量400 U.g-底1物,pH 2.5,温度32℃,底物浓度(原料∶水)1∶2,酶解时间3 h;试验结果还表明,单酶(胃蛋白酶)的酶解蛋白多肽比复合酶(复合风味酶)和双酶(胃蛋白酶 木瓜蛋白酶)的酶解蛋白多肽对ACE活性的抑制能力都强.  相似文献   

3.
蕲蛇蛇毒中凝血酶样酶的分离纯化与特性   总被引:8,自引:1,他引:7       下载免费PDF全文
蕲蛇粗毒经DEAE -SephadexA - 5 0、POROS 5 0HS及TSKG30 0 0SW分离纯化 ,得到 1个具有凝血酶活力的峰 .该峰经SDS -PAGE和PAGE检测均为一条带 ,分子量约 2 8.0kDa ,加DTT处理后 ,拆分为约 14.8kDa的亚基 .其凝血酶活力为 14.7NIHu/mg ,精氨酸酯酶活力为 2 1.98TAMEμmol/mg·min .该组分具有激活因子ⅩⅢ的活性 ,但没有明显的出血反应 .肝素不影响该组分的凝血酶和精氨酸酯酶活性 ,EDTA、PMSF、DFP则会产生不可逆抑制作用 ,表明该组分属于金属蛋白 .  相似文献   

4.
本实验采用超滤法分离发酵乳中的ACE抑制肽,研究了超滤工艺的主要技术参数。结果表明:截留分子量为5000Da的超滤膜,在压力0.10MPa,温度37℃条件下,能得到具有较高ACE抑制活性的超滤液。  相似文献   

5.
研究目的:创新要点:研究方法:重要结论:酸碱热处理对牛乳酪蛋白源血管紧张素转化酶(ACE)抑制肽的抑制活性、游离氨基、色泽及其毒理特性的影响。在pn9.0-12.0的热处理条件下,牛乳酪蛋白源ACE抑制肽的抑制活性降低,色泽加深。热处理后的ACE抑制肽对Caco-2细胞和ECV-304细胞没有毒性作用。以ACE抑制活性、游离氨基、色差值和细胞存活率为检测指标,研究了酸碱热处理对ACE抑制肽的稳定性和毒理特性影响。高温和碱性热处理能破坏酪蛋白源ACE抑制肽的稳定性(见图1~3)。  相似文献   

6.
对3个厂家(Y1,Y2,Y3)生产的永川豆豉的理化指标、水提物血管紧张素转化酶(ACE)抑制活性等指标进行测定与评价,分别用直接干燥法、灼烧重量法、半微量凯氏定氮法、索氏抽提法对其水分、灰分、总蛋白、脂肪等营养指标进行测定,还原糖和总糖百分比通过DNS比色法测定,褐变度和ACE抑制活性分别采用分光光度法和HPLC法测定.结果显示,样品Y2的ACE抑制率和脂肪百分比均最高,分别为83.74%,12.92%;Y1中蛋白质百分比和褐变程度最高,其余指标为Y3最高,说明不同厂家生产的豆豉产品,其营养、感官及功能活性等指标均存在一定差异,工艺过程对豆豉相关品质的影响需要进一步研究.  相似文献   

7.
为了验证大豆多肽血管紧张素转换酶(ACE)抑制活性的生物可获得性,采用Alcalase蛋白酶催化大豆蛋白水解获得了3种水解程度不同的大豆多肽,再应用摸拟体外消化方法处理大豆蛋白及其水解产物,并进一步分析了摸拟消化前后大豆多肽结构、性质和ACE抑制活性的变化.结果显示:3个大豆多肽的相对分子质量均小于16000,且水解度越高,TCA可溶性蛋白含量就越高;经过摸拟体外消化,大豆蛋白出现降解,其分子大小和性质与大豆多肽趋于一致,大豆多肽则进一步降解;3种大豆多肽的ACE抑制活性在经过摸拟体外消化后显著下降,大豆蛋白的ACE抑制活性则显著上升,两者之间没有显著差异,表明虽然Alcalase对大豆蛋白的酶促处理能够释放降血压肽,但经过模拟体外消化后其ACE抑制活性又会下降,而直接口服大豆蛋白有可能获得同样的降血压效果.  相似文献   

8.
对3个厂家(Y1,Y2,Y3)生产的永川豆豉的理化指标、水提物血管紧张素转化酶(ACE)抑制活性等指标进行测定与评价,分别用直接干燥法、灼烧重量法、半微量凯氏定氮法、索氏抽提法对其水分、灰分、总蛋白、脂肪等营养指标进行测定,还原糖和总糖百分比通过DNS比色法测定,褐变度和ACE抑制活性分别采用分光光度法和HPLC法测定.结果显示,样品Y2的ACE抑制率和脂肪百分比均最高,分别为83.74%,12.92%;Y1中蛋白质百分比和褐变程度最高,其余指标为Y3最高,说明不同厂家生产的豆豉产品,其营养、感官及功能活性等指标均存在一定差异,工艺过程对豆豉相关品质的影响需要进一步研究.  相似文献   

9.
以文冠果蛋白为研究对象,采用酶解法制备文冠果蛋白酶解肽,并对其体外抗高血压活性进行研究。以水解度为指标确定酶解条件。蛋白水解物经超滤得到分子量为1k Da,1~5 k Da和5 k Da 3个区段的多肽组分,测定其对血管紧张素转化酶(Angiotensin Converting Enzyme,ACE)的抑制率。最佳酶解条件为:底物质量浓度40g/L,加酶量8%(质量分数)(碱性蛋白酶),酶解时间175 min,酶解温度55℃和酶解p H 9.0,此条件下水解度最高为22.97%;3种多肽组分中1k Da的ACE抑制率最高为83.43%,其半抑制浓度(50%inhibitory concentration,IC50)为0.394 mg/m L。文冠果蛋白酶解多肽具有显著的体外抗ACE活性,可作为降血压肽的开发原料。  相似文献   

10.
枯草芽孢杆菌(Bacillus subtilis)LL18-4菌株分泌物中的类细菌素通过(NH4)2SO4盐析法粗提后,经过SephadexG-75、DEAE-Sephadex A 50和Sephacryl S-200HR分步柱层析,经SDS-PAGE电泳检测到单一蛋白质条带,分子量约为60KD. 该类细菌素在酸性条件下及80%饱和度的(NH4)2SO4溶液中具有较高的稳定性,可4℃放置3个月仍保持大部分活性;对有机溶剂也有一定的耐受性:Mg2+能提高蛋白的抑菌活性.  相似文献   

11.
印刷线路板热分解动力学特性   总被引:22,自引:1,他引:21  
应用热重法对印刷线路板在不同的氮气/氧气气氛、不同的加热速率条件下的反应动力学进行研究。采用Friedman多个升温速率法分析反应机理,得到了不同氧浓度和加热速率下的反应动力学方程及动力学参数。研究表明:在氧气存在条件下,样品热分解反应分为两个阶段,加热速率的提高使热分解反应推迟,两个阶段反应过程的表观活化能有很大差别,反应分别受不同的化学反应机理控制。  相似文献   

12.
为保证傍河水源地水资源的可持续开发利用,并尽量减少由此对生态环境造成的负面影响,对水源地的开采井群进行优化设计是必要的。本研究以开采量(20×104 m3?d?1)和地下水位允许降深(14 m)为目标函数,以袭夺江水比例、地下水位降落漏斗范围、理论单井供水能力为约束条件,以开采井数量、井间距离、井河距离3个设计参数为变量,应用Visual MODFLOW 2010.0软件对地下水流场的演化规律进行了模拟预测,并基于预测结果对设计方案进行了比选,得到了最优参数组合。结果表明:9口开采井、井间距离为100 m、井河距离为50 m为最优方案;在该方案条件下,傍河水源地的供水能力为2.1×105 m3?d?1,其中袭夺的江水量占66%;形成的地下水位降落漏斗面积为2.8×106 m2,中心区降深为11.5 m,对环境产生的扰动最小,环境负效应也最小。   相似文献   

13.
通过对肌红蛋白和牛血清白蛋白混合蛋白样品分离,研究了非对称流场流分离技术(AF4)分离蛋白时需要优化的参数及各个参数对分离效果的影响。首先应用正交设计实验考察样品进样量、横向流速、进检测器流速、聚焦时间对分离效果的影响,得到最大影响因素为横向流速,最优分离条件为:样品进样量20μL、横向流速5mL/min、进检测器流速0.2mL/min、聚焦时间6min。经验证此最优分离条件下分离度达到2.5。随后在最优分离条件下分别考察膜材料、缓冲盐浓度、分离腔室厚度对非对称流场流分离效果的影响。结果表明,截留膜选用再生纤维素膜,流动相缓冲盐浓度为20mmol/L时,满足非对称流场流分离技术分离蛋白样品的分离要求,随着腔室厚度的提高,分离度进一步增大。  相似文献   

14.
The influence of Nd addition on the glass-forming ability (GFA), microhardness, and corrosion resistance of Mg60?xCu40Ndx (x = 5, 10, 15, 20, and 25, at%) alloys were investigated by differential scanning calorimetry, Vickers-type hardness tests, and electrochemical me-thods. The results suggest that the GFA and microhardness of the amorphous alloys increase until the Nd content reaches 20at%. The corro-sion potential and corrosion current density obtained from the Tafel curves indicate that the Mg35Cu40Nd25 ternary alloy exhibits the best corrosion resistance among the investigated alloys. Notably, nanoporous copper (NPC) was synthesized through a single-step dealloying of Mg60?xCu40Ndx (x = 5, 10, 15, 20, and 25) ternary alloys in 0.04 mol·L?1 H2SO4 solution under free corrosion conditions. The influence of dealloying process parameters, such as dealloying time and temperature, on the microstructure of the ribbons was also studied using the sur-face diffusivity theory. The formation mechanism of dealloyed samples with a multilayered structure was also discussed.  相似文献   

15.
【目的】应用正交试验,研究了娄彻氏链霉菌发酵对水稻秸秆加工性能的影响。【方法】在30℃、含水率为65%的条件下,探究了发酵时间、接种量、碳氮比3因素对水稻秸秆质量损失率,纤维素、半纤维素和木质素的降解率,以及最大压应力和黏度(加工性能)的影响,并利用SPSS 19.0软件分析了降解条件与水稻秸秆理化性能的相关性。【结果】娄彻氏链霉菌发酵条件对水稻秸秆的降解性与加工性能的影响顺序为:发酵时间碳氮比接种量;通过相关性分析可得,发酵时间与纤维素、半纤维素和木质素的降解率以及质量损失率极显著正相关,与秸秆的最大压应力和黏度显著负相关。发酵的最优条件为:碳氮比为25,接种量为0.8%,发酵时间为20 d。此时水稻秸秆的最大压应力为5.62 MPa,较原秸秆降低了10.74%;黏度为415.8 m Pa"s,较原秸秆提高了29.7%;平衡扭矩则降低了18.2%。微观结构(SEM)显示发酵后水稻秸秆表面粗糙、凹凸不平,内部结构发生了变化。【结论】娄彻氏链霉菌发酵改变了水稻秸秆的物理化学结构,改善了水稻秸秆的加工性能。  相似文献   

16.
In this study, we used 127 double haploid (DH) lines to analyze agricultural traits of rice. The DH lines, derived from a ZYQ8 (indica)/JX17 (japonica) cross by anther culture, contained 160 RFLP and 83 SSR markers. Unconditional and conditional quantitative trait loci (QTL) mapping was conducted to analyze plant height (PH) and tillers per plant (TP) at ?ve growth stages that were grown at two nitrogen levels. Fourteen PH and 13 TP unconditional QTL were identified in the di?erent growth stages, including 19 QTL from high-nitrogen (HN) and 14 QTL from low-nitrogen (LN) conditions. The conditional QTL for 14 genomic regions under LN/HN conditions showed that there was a significant effect on PH and TP across the different stages. Only one conditional QTL, ph2-3, was unable to be detected in unconditional mapping. More QTL were detected in the ?rst four rice growth stages than in the final stage. Furthermore, a line from the DH mapping population, DH78, was identified in extreme phenotypes of PH and TP that exhibited dwarfism and less-tiller (dft) characters. The gene dft1 was mapped to chromosome 2 using a backcrossed population of DH78/JX17 through a mapbased cloning strategy. The location of dft1 coincided with the mapping region of the small-LOD peak, QTL ph2 and tp2, which were identified in plants grown in low-nitrogen conditions. Further backcrossing and fine-mapping successfully delimited the dft1 locus to a 91 kb region.  相似文献   

17.
This study aims to investigate tribological properties in a siliconized graphite(СГ-П-0.5) and hierarchically hybrid Si C/C composites at the load ranging from 10-40 N under dry air/water lubrication conditions. A feasible liquid silicon infiltration(LSI) was used to fabricate the Si C/C composites. Morphology and phase identification of two materials were characterized and analyzed by scanning electron microscope(SEM) and energy dispersive spectrometer(EDS). An image feature extraction was used to post-process the data of wear test, further to gain the wear properties of the samples. The results demonstrated that a lower coefficient of friction(COF) and wear rate can be achieved in the LSI Si C composites than that in the sample of СГ-П-0.5. Both COF decreased under waterlubricated conditions, compared with that under the dry air lubrication. The excellent tribological properties in two materials can be due mainly to the microstructure of the СГ-П-0.5 sample, showing much more graphite and Si dispersed on the matrix. The СГ-П-0.5 sample indicated the typical oxidative wear mechanism, whereas, the sample of LSI Si C demonstrated the combined oxidative and fatigue wear. This finding can provide a promising new siliconized graphite materials for ceramic rolling bearings.  相似文献   

18.
以CuSO4?5H2O、AlCl3?6H2O和Na2CO3为原料,采用改进的丙三醇-水热法,将预先制备的碱式碳酸铜前躯体与AlCl3?6H2O及少量丙三醇溶液在120℃水热反应18h合成了Cu-Al-HTLc类水滑石样品. 分析了不同介质合成条件对Cu-Al-HTLc类水滑石样品特征的影响,并采用XRD、SEM、N2吸附-解吸等表征手段进行了物相、晶体形貌结构和比表面积分析,结果表明样品的分散性好、层状结构显著、晶型好.  相似文献   

19.
鲫鱼斯坦尼小体降血钙因子的初步鉴定   总被引:3,自引:0,他引:3  
采用向春季鲫鱼体腔注射Cacl2,导致身钙升高的方法,使其含有降血钙因子——斯氏降钙素的斯坦尼小体Ⅰ型细胞的分泌颗粒应答性地释放殆尽。然后对这种不含斯氏降钙素的斯坦尼小体组织匀浆和含有斯氏降钙素的斯坦尼小体组织匀浆的电泳带进行比较、分析,从而鉴定出鲫鱼坦尼小体中的降血钙因子是一种表观分子量为48kD的糖蛋白,其解聚物的分子量为24kD。  相似文献   

20.
Fe/HNT (Iron/Halloysite-nanotube) heterogeneous semiconductor catalysts operating effectively under visible light were developed by using FeCl3, FeSO4 and Fe(OH)3 sludge precipitated after electro-Fenton process and named as Fe/HNT-I, Fe/HNT-II and Fe/HNT-III, respectively. Chemical configuration and particle morphology of the catalysts were characterized with XRD, SEM-EDS and UV–vis DRS. Effect of the developed Fe/HNT photocatalysts was investigated for the degradation of Reactive Orange 16 (RO16) textile dye under visible light. The photocatalytic decolorization of RO16 was 95.6%, 99.3% and 96.6%, respectively. It was found that the photocatalytic performance of Fe/HNT-III catalyst under visible light was effective compared to Fe/HNT-I and Fe/HNT-II. The iron ratio in the catalyst's structure (Fe:HNT ratio 0.25, 0.5 and 0.75 (w/w)) and pH value (4, 7 and 9) in production phase were also changed to investigate the photocatalytic effect of Fe/HNT-III. An Fe:HNT ratio of 0.25 and a pH of 4 were determined as the optimum conditions for catalyst production. Optimum H2O2 dosage value was also investigated for photocatalytic oxidation process and determined to be 10 ?mM. Finally, the optimum conditions were further used for the degradation of Terbinafine hydrochloride (TerHCl) active drug and the treatment of wastewater from the textile and pharmaceutical industries.  相似文献   

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