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1.
超声波对菠萝果蛋白酶活性和光谱的影响   总被引:17,自引:1,他引:16       下载免费PDF全文
以菠萝果为材料,用盐析法制备菠萝果蛋白酶粗酶,进一步经SephadexG-50和DEAE-纤维素柱层析纯化,其SDS—PAGE呈单一的电泳带,并获得了菠萝果蛋白酶结晶。一定参数的超声作用可以使酶活力提高,经光谱分析,超声处理后酶的吸收光谱不改变,而荧光发射峰由336nm红移到339nm,紫外差示光谱在一定的波长也呈现出明显的正峰和负峰。本文讨论了超声波影响菠萝果蛋白酶活性的机理。  相似文献   

2.
研究了动态高压微射流技术对木瓜蛋白酶活性的影响,并以荧光光谱为检测手段对木瓜蛋白酶的分子构象进行表征。结果显示,动态高压微射流处理(120~180 MPa)后,木瓜蛋白酶酶活降低。经180 MPa处理1次,木瓜蛋白酶相对酶活降至90.04%。随着处理压力的增加,木瓜蛋白酶分子、酪氨酸残基、色氨酸残基的荧光发射峰位置分别从对照组的334、285、277.5 nm红移至140 MPa处理组的335.5、285.5、278.5 nm,然后回移至180 MPa处理组的334、285、278 nm。在0~4℃放置24 h后,酶活进一步降低,木瓜蛋白酶和酪氨酸残基的荧光强度出现波动(降低、上升然后再降低),表明动态高压微射流处理(120~180 MPa)改变木瓜蛋白酶分子构象的效果较为明显,形成的新构象稳定性低。  相似文献   

3.
胡松青  李琳  陈玲 《应用声学》2005,24(5):323-328
采用不同电功率的超声波处理了聚乙二醇(PEG6000)溶液。凝胶渗透色谱(GPC)分析超声处理后的PEG溶液发现,当超声电功率超过250W时,PEG分子量随超声波作用强度的增大而减少,随超声波作用时间的延长而增大;在电功率超过250W超声波作用下,傅立叶红外光谱(FT-IR)分析表明,组成PEG的单体没有明显改变,但是,羟基含量分析表明,PEG固体样品中的羟基含量有所减少。结合实验结果,根据高分子化学、有机化学和超声化学中相关理论对PEG超声化学反应机理进行了探讨,认为:当超声波作用于PEG溶液时,同时存在有PEG的缩水聚合反应和自由基降解反应,当频率为20-25kHz、电功率为250-600W的超声作用于PEG6000溶液时,缩水聚合反应占主导地位。  相似文献   

4.
超声波处理对脱脂麦胚分离蛋白结构的变化研究   总被引:4,自引:0,他引:4  
Liu B  Ma HL  Li SJ  Tian WM  Wu BG 《光谱学与光谱分析》2011,31(8):2220-2225
应用傅里叶红外光谱(FTIR)、荧光光谱研究超声处理对脱脂麦胚分离蛋白(DWGP)结构的变化,建立DWGP高效酶解与其结构变化之间的关系.研究发现,超声处理均可提高DWGP的酶解效果,特别是经超声功率600 W、时间10 min处理后,酶解液抑制活性与对照组相比提高了23.96%.通过荧光光谱发现,超声作用改变DWGP溶液荧光强度,适当超声处理可使蛋白分子伸展、生色基团外露,有助于蛋白酶解后获得活性更高的抑制肽.采用对FTIR谱酰胺I带进行曲线拟合的方法,定量分析了不同超声功率、时间对DWGP二级结构的影响,发现超声作用使β-折叠相对含量下降而β-转角含量增加,这可能是DWGP酶解后获得高效抑制肽的主要原因.  相似文献   

5.
在弱酸性介质中,酪蛋白与亚硝基红盐结合形成的缔合微粒导致体系共振散射强度急剧增加,并产生新的共振散射峰,最强散射峰为514nm处。基于木瓜蛋白酶催化酪蛋白水解,酶的活力在一定条件下与共振散射强度的降低有良好的线性关系,回归方程△I=885.9C+20.35(r=0.9891),检出限为0.01U/mL,建立了一种测定木瓜蛋白酶活力的简便、快速的新方法,并用于嫩肉粉中木瓜蛋白酶活力的测定。  相似文献   

6.
超声波加工新技术   总被引:2,自引:0,他引:2  
超声波在国防和国民经济中的用途可分为两大类,一类是检测超声,另一类是功率超声.检测超声是利用超声波来进行各种检验和测量的技术.而功率超声则是利用超声波振动形式的能量使物质的一些物理、化学和生物性质或状态发生改变,或者使这种改变过程加快的这样一门技术,与检测超声不同,功率超声是用能量来对物质进行处理、加工.它最常用的频率是从几千赫到几十千赫,而功率由几瓦到几万瓦.由于功率超声加工技术具有许多特点,与其他加工技术相比,常能大幅度提高加工速度和效率,提高加工质量和完成一般技术所不能完成的工作.因此一在…  相似文献   

7.
脉冲电场对木瓜蛋白酶影响的荧光光谱分析   总被引:2,自引:0,他引:2  
木瓜蛋白酶溶液在电场强度为50 kV·cm-1,频率1 500 Hz,脉冲宽度40μs的脉冲电场下接受19 800个脉冲处理后,其活性降低了56.5%.文章采用荧光偏光光谱对处理前后的样品进行了分析.处理后酶样的荧光强度明显大于处理前,在峰值位置其荧光强度增加超过50%,峰位从342 nm移到了346 nm左右,其荧光偏振幅度明显减小.由此推断出木瓜蛋白酶经脉冲电场处理后酶蛋白的α-螺旋结构松散拉伸,分子内部的氨基酸残基暴露于分子表面,并有部分发生离解游离于溶液中,导致活性部位的结构发生变化,最终导致酶失活.  相似文献   

8.
双低频超声处理偶氮类染料模拟废水的研究   总被引:2,自引:1,他引:2       下载免费PDF全文
对用双低频超声波处理偶氮染料活性艳红X-3B模拟废水进行了实验研究。探讨了不同超声波之间的功率搭配和超声波探头之间的距离对处理效果的影响。实验表明双频超声降解效果优于单频超声,双频超声存在最佳功率搭配。在给定的实验范围内,两个超声波探头之间的最佳距离为1.5cm,US/Fenton处理污染物的效果(η值为94.90%)高于US与Fenton处理效果之和7.1个百分点。通过UV-Vis分析,观察到活性艳红X-3B处理60min后基本被矿化。  相似文献   

9.
超声处理对ZnO薄膜光致发光特性的影响   总被引:3,自引:0,他引:3       下载免费PDF全文
袁艳红  侯洵  高恒 《物理学报》2006,55(1):446-449
对于结晶状态好的ZnO薄膜,测量了其光致发光(PL)光谱,发射光谱中只发现了峰值波长约389 nm的近紫外光.样品进行超声处理后,发射谱中不仅观察到近紫外峰,又观察到波长约508 nm的绿光峰.绿光峰的强度比近紫外光的强度强得多,且近紫外峰红移.进一步的热处理使绿光峰大大增强.超声处理改变了ZnO薄膜的质量和结晶状态,使晶格中产生氧空位.处理过程中的热效应使得薄膜晶格振动加剧.当晶格振动加剧到一定程度,晶格中的氧脱离格点形成氧空位.510 nm左右的绿色发光峰是ZnO晶体中的氧空位产生的.薄膜的温度越高, 关键词: ZnO薄膜 超声 光致发光  相似文献   

10.
实验研究了超声波光生物制氢反应器的启动工艺以及反应器的产氢特性,探讨了超声时间和超声功率对反应器产氢性能的影响。超声波光生物反应器的启动实验进行了96 h,此时反应器光合细菌生物量和反应液pH值趋于稳定,启动完成。在系统稳定运行后,随着超声时间、超声功率的增大,超声波光生物制氢反应器的产氢速率和产氢得率呈先增加后降低的趋势,然而葡萄糖去除率却随着超声时间的增加而增大。  相似文献   

11.
The aim of the study was to investigate the impact of sodium alginate (ALG) pretreated by ultrasound on the enzyme activity, structure, conformation and molecular weight and distribution of papain. ALG solutions were pretreated with ultrasound at varying power (0.05, 0.15, 0.25, 0.35, 0.45 W/cm2), 135 kHz, 50 °C for 20 min. The maximum relative activity of papain increased by 10.53% when mixed with ALG pretreated by ultrasound at 0.25 W/cm2, compared with the untreated ALG. The influence of ultrasound pretreated ALG on the conformation and secondary structure of papain were assessed by fluorescence spectroscopy and circular dichroism spectroscopy. The fluorescence spectra revealed that ultrasound pretreated ALG increased the number of tryptophan on papain surface, especially at 0.25 W/cm2. It indicated that ultrasound pretreatment induced molecular unfolding, causing the exposure of more hydrophobic groups and regions from inside to the outside of the papain molecules. Furthermore, ultrasound pretreated ALG resulted in minor changes in the secondary structure of the papain. The content of α-helix was slightly increased after ultrasound pretreatment and no significant change was observed at different ultrasound powers. ALG pretreated by ultrasound enhanced the stability of the secondary structure of papain, especially at 0.25 W/cm2. The free sulfhydryl (SH) content of papain was slightly increased and then decreased with the increase of ultrasonic power. The maximum content of free SH was observed at 0.25 W/cm2, under which the content of the free SH increased by 6.36% compared with the untreated ALG. Dynamic light scattering showed that the effect of ultrasound treatment was mainly the homogenization of the ALG particles in the mixed dispersion. The gel permeation chromatography coupled with the multi-angle laser light scattering photometer analysis showed that the molecular weight (Mw) of papain/ALG was decreased and then increased with the ultrasonic pretreatment. Results demonstrated that the activity of immobilized papain improved by ultrasonic pretreatment was mainly caused by the variation of the conformation of papain and the effect of interactions between papain and ALG. This study is important to explain the intermolecular interactions of biopolymers and the mechanism of enzyme immobilization treated by ultrasound in improving the enzymatic activity. As expected, ALG pretreated by appropriate ultrasound is promising as a bioactive compound carrier in the field of immobilized enzyme.  相似文献   

12.
The effect of ultrasound on the activity of α-amylase, papain and pepsin was investigated and the mechanism of the effect was explored by determining their conformational changes. With the irradiation of power ultrasound, the activity of α-amylase and papain was inhibited, while the activity of pepsin was activated. According to the analysis of circular dichroism, Fourier transform infrared and fluorescence spectroscopy, the πo  π1 amide transitions and secondary structural components, especially β-sheet, of these three enzymes were significantly influenced by ultrasound. The tryptophan fluorescence intensity of the three enzymes was also observed to be affected by sonication. Furthermore, it was found that the pepsin molecule might gradually be resistant to prolonged ultrasonic treatment and recover from the ultrasound-induced damage to its original structure. The results suggested that the activity of α-amylase, papain and pepsin could be modified by ultrasonic treatment mainly due to the variation of their secondary and tertiary structures.  相似文献   

13.
采用荧光光谱、圆二色谱(CD)和紫外光谱研究了十六烷基三甲基溴化铵(CTAB)在NaHPO4-NaH2PO4缓冲溶液中对木瓜酶构象变化及其酶活的影响,并探讨了CTAB与木瓜酶的作用机理.荧光光谱表明,在CTAB存在下,木瓜酶的荧光强度增强,荧光峰发生红移,CTAB使木瓜酶分子链趋于伸展,酪氨酸等发色基团更多地暴露在水中.CD谱表明,当CTAB浓度(CCTAB)为0.5 mmol/L时,木瓜酶的a-螺旋构象和β-折叠构象含量比纯木瓜酶(Papain)体系分别增加了1.3%和0.1%,回转构象和无定型构象含量则分别减少了0.3%和1.2%.酶活测定结果表明,CTAB对木瓜酶的酶活有较大影响,当CCTAB由0增加到 1.5mmol/L时,木瓜酶酶活由11.2×105U/g增大到16.3×105U/g,当CCTAB由1.5mmol/L增加到3.5mmol/L时,木瓜酶的酶活又由峰值(16.3×105U/g)降到11.7×105U/g.CTAB使木瓜酶酶活增强与木瓜酶的构象有序度提高有关.  相似文献   

14.
绿松石常见蓝色、绿色和杂色等颜色,其中蓝色和绿色者因颜色鲜艳,价值最高,因此绿松石优化处理品也多为蓝色和绿色。利用有机树脂对质松色浅的绿松石进行充填处理(简称“有机充填”)是目前最主要的绿松石优化处理方式,常见浸胶和注胶两种处理类型。采用基础宝石学测试、红外吸收光谱仪、三维荧光光谱仪和X射线荧光光谱仪等测试技术分别对天然绿松石、浸胶和注胶充填处理绿松石的宝石学特征及谱学特征进行了系统的对比分析和研究。研究结果显示,天然绿松石紫外灯长波下具中等至弱荧光,荧光强度与色调和致密程度相关,浸胶绿松石长波荧光强于相同颜色天然绿松石,注胶绿松石长、短波下均具有中等至弱荧光。浸胶绿松石的红外吸收光谱显示,除绿松石本身特征峰外,还可见1 739 cm-1附近ν(C═O)吸收峰和2 926和2 851 cm-1亚甲基的吸收峰,注胶绿松石除羰基及亚甲基吸收峰更强外,还可见1 508 cm-1处苯环骨架特征吸收峰。三维荧光光谱测试显示,天然蓝色绿松石具有一个Ex为370 nm的中等强度特征荧光峰、半峰宽约为100 nm,绿色、杂色系和低致密度绿松石荧光极弱;蓝色浸胶绿松石具有Ex为380~400 nm内的强对称荧光特征峰,绿色浸胶绿松石可见一较强的荧光特征峰,半峰宽约为80 nm;蓝色注胶绿松石具有两个Ex分别为278和390 nm附近的较弱强度荧光特征峰,绿色注胶绿松石具有中等强度的荧光峰、半峰宽约为150 nm,荧光峰区域范围增大可能因为含有较多有机物。结合X射线荧光光谱仪分析Fe对绿松石的荧光会产生一定抑制作用。绿松石荧光特征和三维荧光光谱测试作为无损检测技术,具有测试简便、快捷、有效的特点,对准确鉴定绿松石和有机充填处理品具有重要的现实意义。  相似文献   

15.
Metastable-induced electron spectroscopy (MIES) together with ultraviolet photoemission spectroscopy (UPS) was applied to the analysis of the surface electronic structure of chemical-vapor-deposited diamond films. The films were grown in a microwave plasma, and their surfaces were terminated by hydrogen. The MIES spectrum measured at an as-deposited surface contains peaks due to adsorbates. When this surface was annealed at 400 °C, those peaks were depressed, and the spectrum showed a similar structure to that of UPS. Once the surface was re-hydrogenated, the MIES spectrum rose up at lower energies than the UPS spectrum did for surfaces annealed at lower temperatures. Finally after annealing at 1000 °C, the cutoff energies of MIES and UPS converged at nearly the same values. The result demonstrates that the MIES detects a surface potential which changes locally at the hydrogen-terminated surfaces.  相似文献   

16.
Multi-walled carbon nanotubes (MWNTs)/Cu-doped ZnO composite powders were prepared by co-precipitation method, and were characterized by X-ray diffraction, electron microscopy, fluorescence spectrum, and ultraviolet spectrum. Experimental results show that the MWNTs can be modified by Cu-doped ZnO nanoparticles with hexagonal wurtzite structure after annealed at 450?°C, and the nanoparticle size is about 15?nm. Two ultraviolet (UV) peaks and a green band centered at about 510?nm are observed in the fluorescence spectrum of MWNTs/Cu-doped ZnO composite powder annealed at 450?°C. Furthermore, MWNTs and Cu doping significantly improve the UV absorption ability of ZnO.  相似文献   

17.
采用紫外、荧光和圆二色等光谱技术研究了阴离子表面活性剂十二烷基硫酸钠(SDS)对木瓜酶酶活力及其构象变化的影响.结果表明:(1)SDS对木瓜酶酶活力的影响与pH有关,pH=8.00时,SDS对木瓜酶酶活力有增强作用,pH=6.30时,除了在SDS的临界胶束浓度(cmc)时木瓜酶酶活力得到增强外,其他浓度下SDS对木瓜酶酶活力没有影响,pH=9.50时,SDS对木瓜酶酶活力产生抑制作用.(2)SDS对木瓜酶的荧光产生淬灭,0.1cmc的SDS木瓜酶荧光峰红移,而SDS浓度≥1cmc后则使之蓝移;(3)当[SDS]<cmc时,木瓜酶的α-螺旋、β-折叠、回转等有序结构的含量减少而无定形结构含量增加,当[SDS]>cmc后,木瓜酶的α-螺旋、β-折叠构型含量有所增加,无定形构型含量则有所减少.有序结构的含量越大,酶活力越强.  相似文献   

18.
为了研究不同黄疸治疗仪光源的发光光谱对新生儿产生紫外辐射、热辐射等潜在的光生物安全问题,本文利用光辐射安全测定系统OST-300对传统蓝光荧光灯、普通蓝光LED灯以及经简单遗传算法计算与拟合的蓝光LED灯进行了测试与对比分析。实验结果表明:传统蓝光荧光灯在315,330,365 nm的紫外光处有明显的波峰出现,且峰值波长在365 nm处较为明显;传统蓝光荧光灯在老化后其蓝光光谱光衰严重,且存在大量的红外光线;而基于简单遗传算法计算与拟合的蓝光LED发光光谱与体内胆红素的吸收光谱相吻合,能避免对新生儿的光辐射危害。因此,本文提出的蓝光LED是治疗新生儿黄疸的理想光源。  相似文献   

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