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1.
长毛对虾碱性磷酸酶性质   总被引:43,自引:5,他引:43  
从长毛对虾内脏物分离提纯碱性磷酸酶,经快速蛋白液相色谱(FPIC)检验为单一蛋白纯.研究该酶的性质,酶的紫外吸收特征峰在278nm处,荧光激发峰在282nm处,发射光谱特征峰在340nm处.酶的分子量为82000道尔顿.酶水解PNPP的最适温度为47℃、最适pH为8.2.在37℃、pH8.3下,酶的Km值为8.0×10-4mol/L.Mg2+对该酶有激活作用,Cu2+、Hg2+甲醇、乙醇,乙二醇则表现抑制作用.Hg2+的抑制作用表现为反竞争性类型,其抑制常数为9.0×10-5mol/L.  相似文献   

2.
长毛对虾酸性磷酸酶的纯化与性质   总被引:32,自引:2,他引:32  
分别从健康和患病长毛对虾(Penaeuspenicilatus)肌肉提取一种酸性磷酸酶(AC-Pae,EC.3.1.3.2.),进一步用硫酸铵分级分离,SephadexG-200柱纯化,经聚丙烯酰胺凝胶电泳,并于BeckmanDU-8B紫外分光光度计扫描为单一区带酶液。该酶紫外吸峰在280nm处,荧光激发峰在284nm处,发射峰在347nm处。酶的分子量为73000道尔顿,等电点为4.7酶水解对硝基苯磷酸二钠(PUPP)最适pH为4.5,最适温度40℃。健康虾与病虾酶的活化能分别为41.03kJ/mol·L和45.78kJ/mol·L,米多常数km值分别为0.80×10-4mol/L和1.43×10-4mol/L。重金属离子Cu2+,Hg2+,有机溶剂甲醇,乙醇,乙二醇等对ACPase有明显的抑制作用。  相似文献   

3.
酶法水解乳清蛋白过程的优化   总被引:1,自引:0,他引:1  
以浓缩乳清蛋白为原料,选择碱性蛋白酶(Alcalase)水解乳清蛋白。分析了pH、温度、酶和底物比(E/S)和反应时间等因素对乳清蛋白水解的影响。通过响应面法分析,确定了碱性蛋白酶(Alcalase)酶解乳清蛋白的最佳水解条件为:pH8.5、反应温度55℃、酶和底物比0.05。水解3.0h,水解度为19.34%。  相似文献   

4.
对蚝油的酶水解工艺条件进行初步研究。结果表明:酶水解的最佳条件为酸性蛋白酶,酶水解温度50℃,超始pH2.5,酶用量5000u/g,酶水解时间4-5h。  相似文献   

5.
醇盐受控水解法制备YSZ超细粉及其表征   总被引:1,自引:0,他引:1  
利用正丙醇锆受控水解方法制备YSZ粉.研究在正丙醇锆-硝酸钇-乙酰丙酮体系中,Acac/Zr(mol),H2O/Zr(mol)对正丙醇锆水解影响.采用TG-DTA,XRD,Raman光谱,BET,TEM等手段对YSZ粉体进行表征.发现本体系获得的粉体立方相成相温度可低至350℃,颗粒度在10nm左右  相似文献   

6.
通过一系列酶促反应动力学的研究,结果表明赤小豆胰蛋白酶抑制剂对人体精子顶体蛋白酶(Acrosin)有较强的不可逆竞争性抑制作用.其Km和Ki值分别为1.86×10-3mol/L和2.1×10-5mol/L.  相似文献   

7.
聚苯乙烯载体亲和层析纯化尿激酶   总被引:2,自引:0,他引:2  
聚苯乙烯经磺化后连接手臂6-氨基己酸,然后偶联配基对氨基苯甲脒,制成亲水性的亲和载体。载体的最适配基密度为每克湿载体32μmol,最适吸附条件为pH7.5、0.05mol/L磷酸缓冲液(含NaCl0.5mol/L)。在pH4.0、0.1mol/L醋酸缓冲溶液(含NaCl0.5mol/L)中,采用0~1mol/L NaSCN梯度洗脱,可将比活8.33μmol·S-1·mg-1的粗酶纯化50倍,收率大于53%。  相似文献   

8.
研究了中性蛋白酶和木瓜蛋白酶对鹅血液的水解作用,并分析了酶用量、温度、时间、pH值等因素对鹅血酶水解的影响。结果表明,双酶水解效果较好,确定了其最适宜的酶解条件:中性蛋白酶,酶底物浓度比(E/S)为4000U/g,pH值为7.0,温度为55℃,时间为5h;木瓜蛋白酶,酶底物浓度比(E/S)为6000U/g,pH值为7.5,温度为50℃,时间为4h。  相似文献   

9.
磷酸盐及其结构类似物对文昌鱼酸性磷酸酶的影响   总被引:3,自引:2,他引:3  
研究了磷酸盐(HPO ̄(2-)_4)及其结构类似物钼酸盐(MoO ̄(2-)_4),钒酸盐(HvO ̄(2-)_4),钨酸盐(WO ̄(2-)_4)对文昌鱼酸性磷酸酶活力的影响及其抑制机理。实验结果表明:磷酸盐对文昌鱼酸性磷酸酶的抑制作用表现为竞争性抑制类型,而其结构类似物则是通过非竞争性抑制的方式抑制酶活力.抑制常数Ki分别为:磷酸盐:3.0×10 ̄(-4)mol/L,钼酸盐:5.5×10 ̄(-7)mol/L,钒酸盐:7.0×10 ̄(-7)mol/L,钨酸盐:3.8×10 ̄(-8)mol/L,用酸盐对酶活力呈时间抑制过程,表明该类似物可能通过氧化—还原这种新的抑制机理来抑制酶的活力。  相似文献   

10.
玉米巯基蛋白酶抑制剂的纯化及部分性质   总被引:4,自引:0,他引:4  
从玉米种子纯化的两种巯基蛋白酶抑制剂(CPI-I和CPI-Ⅱ)分子量分别为9500和13000,经们都只抑制巯基蛋白酶的水解活性,而对丝氨酸蛋白酶则无抑制作用,属于巯基蛋白酶水解抑制剂,它们在pH3.0~11.0或100℃温度范围内保有100%的抑制木瓜蛋白的抑制活性,表明在这些外界条件下其分子非常稳定。  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
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   

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