2001年第23卷总目次

研究报告与简报复合核苷氧钒配合物 ( VRC)的合成及对 RNA酶的抑制效应………………………………………………………………薛德平　颜世庆　王琰　林文玉　白桃　王申五　张礼和　王夔 *( 1 )………………………………………………新型冠醚交联壳聚糖的合成完莉莉　汪玉庭 *( 6)……………………………………………………………………………4 ,4′-二胺基 -2 ,2′,6,6′-四甲基二苯基环己烷的合成与纯化徐利文　杨立明 *( 8)…………………………………………高纯度 meso-四苯基卟啉的合成王君文 *　何明威 ( 9)…………………………………     

透明质酸酶的研究现状及展望

随着分子生物学和蛋白质组学的发展,不同来源的透明质酸酶多样性逐渐被发现,已逐渐应用于医药和工具酶等多个领域。综述了透明质酸酶分类与来源、透明质酸酶抑制剂、应用领域和重组透明质酸酶的制备,并对其未来研究方向进行了展望。     

从适应低温的细菌中提取的低温酶（英）

从覆盖有积雪的土壤中的大麻哈鱼肠的螃蟹肠中分离出了新的细菌苗种，并对它们分泌出的淀粉酶、脂肪酶和蛋白酶的性能进行了研究。发现了一种淀粉酶、一种脂肪酶和三种蛋白酶，它们的最佳活性温度明显地朝低温方向移动，而且活化能有所降低。这些酶在高于最代温度（即３０℃￣４０℃）时迅速失活。结果表明，这些酶具有低温活性。低温活性最好的蛋白酶生产者从大麻哈鱼肠中分离出来的菌种通过１６Ｓｒ核糖核酸分析已验明为黄杆菌属，     

用核磁共振氢谱法研究胸腺嘧啶与过氧化钒配合物的光照射反应

利用核磁共振氢谱的方法,研究在单线态氧的作用下,胸腺嘧啶残基(包括胸腺嘧啶(T)、胸腺嘧啶脱氧核苷(dT)和胸腺嘧啶脱氧核苷酸(TMP))的分解产物。胸腺嘧啶残基与过氧化钒配合物的光照射反应,由过氧化钒配合物光分解所产生的单线态氧使胸腺嘧啶碱基发生了光氧化反应,可能的反应产物通过核磁共振氢谱进行了测定。     

微囊藻毒素降解酶MlrA的结构功能分析

MlrA（亦称microcystinase）是微囊藻毒素（microcystins, MCs）细菌降解途径中负责催化起始反应的关键蛋白酶,其结构特征与底物水解机制尚未明确。使用折叠识别法构建MlrA分子模型,通过分子对接和定点突变分析了酶-底物的结合方式与相互作用,结合蛋白重组表达对酶活性影响机制等进行了探究。结果表明MlrA是定位于细菌细胞质膜的整合膜蛋白,主要由8个跨膜α-螺旋（TM1~8）组成,功能结构域ABI（TM4~7）形成向周质空间开放的底物反应空腔。MlrA催化残基（E172、H205、H260和N264）位于膜内,其侧链投射至反应腔内部。微囊藻毒素LR （MC-LR）采用β-发夹构型与酶结合并将易裂键暴露于水分子附近,其水解机制为E172和H205通过一般碱催化将水分子去质子化激活,对Adda-Arg肽键羰基碳进行亲核攻击;接着H260和N264构成氧阴离子穴以稳定过渡态氧阴离子;最后H205或E172催化胺离去基团发生质子化,使四面体氧阴离子中间体崩解。此外,MlrA不是金属蛋白酶,无法与金属离子（Ⅱ）配位结合,菲咯啉类化合物使酶分子发生非特异性解折叠而失活,EDTA对底物结合位点具有竞争作用。本研究揭示了MlrA的属性与水解机制,为进一步探索MCs微生物降解机理提供一定参考依据。     

茶叶中核糖核酸的分析检测

通过对几种茶叶中核糖核酸（ＲＮＡ）的分离与定性鉴定、电泳分离鉴定及紫外分光光度计定量测定，表明茶叶中确实存在ＲＮＡ，其含量随产地不同而有一定差异，其中滇红、滇绿含量较高，可达１％水平。     

空气强化转炉钒渣湿法浸出行为

钒渣钠化焙烧过程低价钒氧化不充分,不能被浸出,降低了钒渣的浸出率。实验采用蒽醌磺酸钠（ADA）和栲胶作载氧体实现氧的传递,强化低价钒的氧化行为。通过X射线衍射、扫描电镜、紫外光谱以及紫外可见漫反射光谱等检测方法,分析了转炉钒渣浸出反应前后物相变化行为,探索了反应过程机理,证实了其可行性。结果表明,采用ADA和栲胶作载氧体,能将转炉钒渣中的低价钒氧化成可溶的高价钒,实现空气催化氧化高效浸钒。此时,钒浸出率由89.47%分别提高到92.84%和93.64%,且催化剂对体系后续工艺没有不良影响,转炉钒渣中的尾渣含钒量由1.1%分别降至0.52%和0.47%。     

基于结构的HIV-1整合酶抑制剂的虚拟筛选

目的虚拟筛选基于结构的HIV-1整合酶抑制剂。方法从PDB(Protein Data Bank)下载HIV-1整合酶催化核心结构域与LEDGF/p75整合酶结合结构域(integrase binding domain,IBD)的晶体结构(PDB ID:2B4J),通过AutoDockTools对结构进行处理;从ZINC数据库下载化合物结构,用PyRx处理和转换成pdbqt格式,建立一个处理后的化合物数据库;以HIV整合酶为靶点,通过新的虚拟筛选工具PyRx运行AutoDock Vina,对ZINC数据库的化合物进行虚拟筛选;分析得到的小分子抑制剂与整合酶之间的结合情况,并用PyMol对小分子抑制剂与整合酶的结合模式进行3D建模。结果经3轮筛选,发现5个高活性的HIV-1整合酶抑制剂ZINC9486894、ZINC47636331、ZINC57383520、ZINC68964708、ZINC73549421;5个小分子抑制剂与整合酶之间的结合主要是氢键结合力和疏水相互作用。结论通过PyRx运行AutoDock Vina,从ZINC数据库的化合物中筛选出5个新的HIV-1整合酶抑制剂。     

乙酰丙酮氧钒的绿色合成工艺研究

以三氧化二钒为钒源,在体系中引入氧化剂和水夹带剂,合成了乙酰丙酮氧钒,实现了乙酰丙氧钒的绿色连续合成。探讨了空气、过氧化氢和氧气三种氧化剂对乙酰丙酮氧钒合成的影响,对产物进行表征并与商业乙酰丙酮氧钒对比。结果表明,引入氧化剂之后,乙酰丙酮氧钒的产率显著提高,三种氧化剂制得的乙酰丙酮氧钒产率均可达到80%以上,其中氧气氧化效果最好,当氧气流量为200 mL/min,回流2 h时,乙酰丙酮氧钒产率可达90%。XRD、FTIR和TG结果显示,本研究合成的乙酰丙酮氧钒纯度较高,与商业乙酰丙酮氧钒可比。     

液相法制备锆钒蓝色料的研究

介绍了以正硅酸乙酯Si（C2H5O4）、氧氯化锆（ZrOCl2）和氧氯化钒（VOCl3）等为原料，以水和乙醇为介质制备V-ZrSiO4蓝色料超细粉的方法。其中钒均匀地分散固溶在ZrSiO4中，通过系统改变Zr/Si(摩尔比）和V的固溶量可获得最佳呈色效果。通过XRD、DTA-TG和红外光谱的测试和分析明确了在加热过程中颜色变化与钒在ZrSiO4中固溶量的关系，及V^4 取代ZrSiO4中部分Zr^4 形成固溶体的结论。     

Study of the properties of a multi-component inhibitor used for water treatment in cooling circuits

This work is devoted to the corrosion inhibition of a carbon steel in a 200 mg l^–1 NaCl solution by an original multicomponent inhibitor: fatty amines in association with phosphonocarboxylic acid salts and a biocide at low dosage. Its principal advantage is the absence of toxicity and its biodegradability. Steady-state current–voltage curves were combined with electrochemical impedance measurements to characterize the inhibitive properties of each compound and to optimize the concentration of the compounds in the mixture. Phosphonocarboxylic acid salts were observed to act as an anodic inhibitor whereas mixed action was shown for fatty amines. The inhibitive efficiency was increased when the phosphonocarboxylic acid salt concentration was increased whereas for fatty amines an increase of the concentration did not improve corrosion inhibition. Optimal concentrations of fatty amines and phosphonocarboxylic acid salts were determined. X-ray photoelectron spectroscopy (XPS) was used to analyse the layer formed on the metal surface by the inhibitive mixture. The film was composed of an iron oxide/hydroxide mixture incorporating the organic compounds. The inhibitive molecules interact with the iron oxides.     

2,3,5-Triphenyl-2H-tetrazolium Chloride and 2,4,6-Tri（2-pyridyl）-s-triazine on the Corrosion of Mild Steel in HCl

Electrochemical measurement, quantum chemical method, and scanning electron microscopy （SEM） were performed to investigate the inhibitive effect of 2,3,5-triphenyl-2H-tetrazolium chloride （TTC） and 2,4,6-tri（2-pyridyl） -s-triazine（TPT） on the corrosion of mild steel in lmol.L^-1 HCl at room temperature. Impedance spectroscopy measurement showed that the polarization resistance increased and that double layer capacitance decreased with the increase in the inhibitive concentration, and the results of potentiodynamic polarization showed that the inhibitors suppressed both cathodic and anodic processes of steel corrosion without change in the mecha-nism. Higher the orbital density distribution strength of the lowest unoccupied molecular orbital, higher is the molecule dipole, and lower energy gap between the energy of the highest occupied molecular orbital and the energy of the lowest unoccupied molecular orbital resulted in higher inhibitory efficiency. The results of SEM analysis showed that the metal-was protected from aggressive corrosion by the addition of TTC and TPT.     

A comprehensive evaluation of mimosa extract as a corrosion inhibitor on AA6060 alloy in acid rain solution: part I. Electrochemical AC methods

The inhibition effect of mimosa extract on the corrosion of AA6060 aluminum alloy in acid rain solution was investigated by electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy (DEIS). All the studied electrochemical parameters showed good corrosion inhibitive characteristics with respect to the aluminum alloy in the tested solution. Inhibitor efficiency increased with the concentration and attained 45% at 2750 ppm. The advantage of DEIS as a tool for the investigation of corrosion inhibitor influence was discussed.     

Mercapto functional azole compounds as organic corrosion inhibitors in a polyester-melamine coating

The corrosion inhibition of two mercapto functional azole compounds including 2-mercaptobenzimidazole (MBI) and 2-mercaptobenzoxazole (MBO) for mild steel in 1 M NaCl solution was studied by electrochemical impedance spectroscopy (EIS), then their impact on the protective performance of a polyester-melamine coating was evaluated using salt spray. EIS results revealed a higher corrosion inhibitive activity of MBI compared to that of MBO. Corrosion products were examined by SEM-EDX and FTIR. The results showed modification of the corrosion products in the presence of MBI and MBO. The salt spray results revealed an improved corrosion protection of the coatings formulated with MBI and MBO. There was almost no impact of MBI and MBO on adhesion strength and glass transition temperature of the coatings, meaning that their impact on the corrosion protection performance of the formulated coating could only be attributed to their effect on the corrosion products.     

Broad-Spectrum Antifungal Agents: Fluorinated Aryl- and Heteroaryl-Substituted Hydrazones

Fluorinated aryl- and heteroaryl-substituted monohydrazones displayed excellent broad-spectrum activity against various fungal strains, including a panel of clinically relevant Candida auris strains relative to a control antifungal agent, voriconazole (VRC). These monohydrazones displayed less hemolysis of murine red blood cells than that of VRC at the same concentrations, possessed fungicidal activity in a time-kill study, and exhibited no mammalian cell cytotoxicity. In addition, these monohydrazones prevented the formation of biofilms that otherwise block antibiotic effectiveness and did not trigger the development of resistance when exposed to C. auris AR Bank # 0390 over 15 passages.     

Comparative electrochemical studies of zinc chromate and zinc phosphate as corrosion inhibitors for zinc

The anticorrosive performance of two inhibitive pigments, zinc chromate and zinc phosphate, was compared using electrochemical impedance spectroscopy (EIS) and the scanning vibrating electrode technique (SVET) in pigment extracts in 0.1 M NaCl. It was observed that zinc was protected from corrosion in both extracts. In tests using hot dip galvanised steel painted with an epoxy primer incorporating the pigments, the SVET detected the anodic and cathodic distribution along the scribes, although no significant differences were observed among the various primers. On the contrary, EIS was able to distinguish processes occurring on the metal surface exposed by the scribe in different samples. For primers with anticorrosive pigment, a time constant at high frequencies was attributed to a layer of protective nature, probably formed by metal ions from the substrate and inhibitive ions leached from the anticorrosive pigments.     

Corrosion of the stressed pipe steel in carbonate-bicarbonate solution studied by scanning localized electrochemical impedance spectroscopy

Corrosion of X-70 pipe steel as a function of stress distribution was investigated by scanning localized electrochemical impedance spectroscopy (LEIS) technique. The deformation-induced stress, if not sufficiently high, has an inhibitive effect on corrosion reaction, pitting occurrence and crack initiation in pipe steel under high-pH condition. Such an inhibitive effect is due to the enhanced generation of carbonate product and the resultant surface block effect at the stressed zones. The tensile and compressive stresses have identical effect on inhibition of dissolution and pitting of the steel. However, tensile stress enhances the steel dissolution more significantly than compressive stress, and thus, generates more carbonate product, resulting in higher localized impedance. Pits are easy to occur around the neutral axis of the U-bend specimen, where the steel deformation and the resultant stress are ignorable. For pipelines encountering non-uniform stress distribution, the role of stress in crack initiation is critically different. Scanning LEIS technique provides a promising method to map and characterize corrosion of the steel as a function of the stress distribution.     

无机缓蚀剂对铝合金缓蚀作用的研究

通过电化学极化曲线方法和电化学阻抗（ＥＩＳ） 研究了碳族元素含氧酸盐对铝合金在３ ．５ ％ （ 文中所叙述的３－５ ％ 的ＮａＣｌ 均指质量分数,以下不再另注）ＮａＣｌ 溶液中的缓蚀作用．实验结果表明,在氯化钠溶液中添加低浓度的碳酸钠和硅酸钠及高浓度的硅酸钠对铝合金具有较好的缓蚀作用,而添加低浓度的碳酸氢钠后缓蚀效率却很低,甚至没有缓蚀作用．碳酸钠和硅酸钠对铝合金的缓蚀作用是通过抑制铝合金的阴极反应和阳极反应,在铝合金的表面形成不溶的沉淀膜和ｐＨ 效应实现的．碳酸钠在一定程度上能够提高铝合金的抗点蚀的能力．     

Undecyl substitution in imidazole and its action on corrosion inhibition of copper in aerated acidic chloride media

Inhibition of copper corrosion by imidazole (IM) and 1-n-undecyl-imidazole (UDIM) in 0.5 M HCl was investigated by weight-loss measurements, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). 1-n-undecyl-imidazole showed the better inhibitive effect compared with IM. Potentiodynamic polarization results revealed that both IM and UDIM acted as anodic inhibitors, in particular UDIM suppressed anodic current densities significantly. Molecular structure parameters of IM and UDIM were obtained by using an MM2 forcefield program and AM1 quantum chemical calculation. It was found that UDIM has higher levels of HOMO and LUMO energy and a larger electron density in its imidazoly ring. Presented as paper No.13-07 at 14th APCC conference, October 2006, Shanghai, China     

Study of different triazole derivative inhibitors to protect copper against pitting corrosion

Electrochemical experiments were performed to study the inhibitive effect towards copper corrosion of three organic compounds: namely, benzotriazole, 1-hydroxybenzotriazole and 3-amino 1,2,4-triazole. Statistical analysis of pit nucleation times showed that 3-amino 1,2,4-triazole exhibited the most significant inhibitive effect towards pitting. However, impedance measurements revealed that this compound produced a thinning of the passive film. This was corroborated by X-ray photoelectron spectroscopy. Results showed that copper pitting resistance could not be explained only by characterizing the protectiveness of the passive film.