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1.
一种改进的漆酶酶活检测方法   总被引:10,自引:1,他引:10  
以 2 ,2′ -连氮 -双 (3-乙基苯并噻唑 - 6 -磺酸铵 ) (简称ABTS)为漆酶A、B的底物 ,采用UV - 2 2 0 1型紫外 -可见分光光度计连续记录酶反应在 2 5℃ ,4 2 0nm波长下的时间历程曲线 ,并求取最初部分的斜率以计算漆酶酶活的方法 .该方法直观、方便、准确且可靠 .在 2 5℃的 0 .0 4mol/LBritton Robinson缓冲溶液中 ,漆酶A、B的最适 pH值分别为 4 .0和 4 .5 .在 2 5℃最适 pH值的Britton Robinson缓冲液中 ,由双倒数作图法求得漆酶A、B的米氏常数Km 分别是 6 .6 4× 1 0 - 5mol/L和 2 .2 1× 1 0 - 5mol/L ,漆酶A、B的最大米氏反应速度Vmax分别是 1 4 2 5μmol.M (L·min)和 32 5μmol.M (L·min) .漆酶A、B的酶活分别为 2 2 99μmol·min- 1·L- 1和 1 1 4 8μmol·min- 1·L- 1.  相似文献   

2.
本文提出利用循环酶反应器系统研究固定化酶反应机理及测定有关动力学参数的方法。用此法分析以聚丙烯酸甲酯为载体的固定化糖化酶反应动力学获知,该反应为产物竞争性抑制反应,它的表观米氏常数K_M=4.66×10~(-3)mol/L,产物葡萄糖抑制常数K_I=3.78×10~(-3)mol/L,固定化酶的比活性(?)=0.85U/g干固定化酶。  相似文献   

3.
Ag+离子对漆树漆酶催化活性的抑制作用   总被引:5,自引:0,他引:5       下载免费PDF全文
涂楚桥  梁宏  王光辉 《广西科学》1999,6(2):109-110,114
以5,6-二溴-2,3-二氰基氢醌(DDBQH2)为底物,在pH值4.4和30±0.2℃条件下,用分光光度法考察了Ag+离子对漆树漆酶催化活性的影响.结果表明,Ag+离子对DDBQH2的漆酶催化氧化反应有明显的抑制作用,这种作用具有罕见的反竞争性特征,抑制剂常数Ki=(2.1±0.5)×10-5mol.dm-3.  相似文献   

4.
环氧基改性的丙烯酸系树脂含环氧基,环氧基可在温和条件下与蛋白质上的亲核基团氨基反应而实现其固定化.研究了环氧基改性的离子交换树脂固定化漆酶的最优条件和固定化漆酶的酶学性质,结果表明,固定化漆酶时,在硫酸铵浓度为1.5mol·L-1、加酶量0.2U·g-1、pH 6.5、温度35℃条件下固定3h,测得固定化酶活性最好,比活力为0.026U·g-1,活力回收率为3.67%;该固定化酶催化反应的的最适温度为45℃,最适pH 4.5,米氏常数(Km)为1.233×10-3 mmol·L-1.锰离子、铁离子和钙离子在4×10-3~4×10-4 mol·L-1浓度之间时对固定化漆酶活性有抑制作用,在4×10-5~4×10-6 mol·L-1浓度之间时有激活作用.  相似文献   

5.
针对湿法同时脱硫脱硝工艺 ,提出通过构造一个液相反应过程 ,将 NOx 和 SO2 溶解在溶液中生成的 NO2 -2 和 SO2 -3 经过一系列连续的液相离子反应生成有利用价值的 NH+4 ,实现资源的合理利用。在 35°C~ 74°C,离子强度为 0 .5 5 mol/L时对羟胺二磺酸钾磺化反应动力学进行了研究 ,得出反应的动力学方程为 :- dcHIDSdt =kc HON( SO3) 2 -2 · c HSO-3,其中 k=5 .5 0 9× 1 0 8· e-6.154× 10 4 / RT;在5 0°C、离子强度为 0 .31 mol/L~ 0 .65 mol/L时 ,研究了该反应的盐效应 ,结果表明该反应呈负盐效应 ,离子强度为零时 ,有最大的速率常数 k0 =0 .0 2 4 7L /( mol· min)  相似文献   

6.
在HCIO4介质中用光度法研究了抗坏血酸 (HR)与钒 (Ⅴ )氧化还原反应动力学 .通过考察溶液酸度和抗坏血酸浓度对动力学过程的影响 ,求得反应速率方程为-d[H2 R]/dt=k[V(Ⅴ ) ][HR][H ].在 2 5 2℃、μ =1 .0mol/L时 ,反应速率常数k=( 1 .2 2± 0 0 6 )× 1 0 3 (mol/L) -1·min-1;在氧化剂过量情况下 ,抗坏血酸与钒 (Ⅴ )的化学反应计量方程式为HR 2V(Ⅴ )→R 2V(Ⅳ ) H ;推测了可能的单电子转移自由基反应机理  相似文献   

7.
利用两相滴定法在(25±0 5)℃下测定了仲壬基苯氧基乙酸(CA-100)在水中的溶解度S,离解常数Ka,以及庚烷中的二聚常数K2和水-庚烷两相间的分配常数Kd.实验测得S=1 30×10-4mol/L,Ka=2 94×10-4,K2=3 29×102,Kd=4 15×102.  相似文献   

8.
在 p H4.5的醋酸盐缓冲底液中 ,用单扫示波极谱法可获得灵敏的 Mo( ) -5 -溴水杨基荧光酮络合吸附波 ,钼浓度在 1 .0× 1 0 - 8~ 1 .0× 1 0 - 6mol/ L范围内与二阶导数波峰高成正比关系 ,检测限为 7.0× 1 0 - 9mol/ L,测得电活性络合物组成为Mo( )∶ 5 - Br SAF=1∶ 2 ,条件稳定常数为β=5 .4× 1 0 1 0 .  相似文献   

9.
针对湿法同时脱硫脱硝工艺,提出通过构造一个液相反应过程,将Nox和SO2溶解在溶液中生成的NO2-2和SO2-3经过一系列连续的液相离子反应生成有利用价值的NH+4,实现资源的合理利用.在35°C~74°C,离子强度为0.55mol/L时对羟胺二磺酸钾磺化反应动力学进行了研究,得出反应的动力学方程为-(dcHIDS)/(dt)=kcHON(SO3)2-2*cHSO-3,其中k=5.509×108*e-6.154×104/RT;在50°C、离子强度为0.31mol/L~0.65mol/L时,研究了该反应的盐效应,结果表明该反应呈负盐效应,离子强度为零时,有最大的速率常数k0=0.024 7L/(mol*min).  相似文献   

10.
研究了在0.2 mol/L Na2SO4水溶液中乙酰二茂铁(Acetylferrocene,AFc)在玻碳电极上催化氧化N-乙酰-L-半胱氨酸(N-Acetyl-L-Cysteine,NAC)的电化学行为.结果发现,AFc对NAC的电化学氧化有很好的催化作用,该电催化氧化反应在动力学上对AFc及NAC均为一级反应,计时电流实验测得该电催化氧化反应的速率常数为(4.65±0.05)×103mol-1.L.s-1.在AFc浓度一定时,催化氧化峰电流与NAC浓度在(0.2~4)×10-3mol/L的范围内呈良好的线性关系(R=0.998 9),同时运用微分脉冲伏安法对含NAC的药物进行了含量测定,测定结果令人满意.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

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