直链醇对反胶束体系中木素过氧化物酶催化活性的影响

根据研究发现, 在有醇作助表面活性剂的CTAB反胶束中木素过氧化物酶(LiP)不能表现活力, 而在水介质中CTAB对LiP的催化活性影响又不是很大. 为了揭示其中醇的影响, 本工作就不同碳链长度的醇对LiP酶催化性能的影响进行了研究. 由于CTAB反胶束体系中醇浓度较高, 且碳原子数大于4的直链醇在水中的溶解度又很小, 为此采用了LiP可在其中显示催化活性的CTAB正胶束、AOT反胶束和Brij30反胶束作介质, 通过研究这些介质中不同链长的醇对LiP催化活力的影响, 来探讨CTAB反胶束中木素过氧化物酶(LiP)不能表现活力的原因. 结果表明, 不管表面活性剂聚集体的结构、电性质及反胶束大小如何, 只要醇的浓度超过500 mmol•L^－1 (丁醇≥1200 mmol•L^－1), LiP在上述原本可显示活力的介质中均无催化活性. 据此推测CTAB反胶束中木素过氧化物酶(LiP)不能表现活力的原因主要是由助表面活性剂醇造成的.     

Transformation of Tetracycline by Manganese Peroxidase from Phanerochaete chrysosporium

The negative impacts on the ecosystem of antibiotic residues in the environment have become a global concern. However, little is known about the transformation mechanism of antibiotics by manganese peroxidase (MnP) from microorganisms. This work investigated the transformation characteristics, the antibacterial activity of byproducts, and the degradation mechanism of tetracycline (TC) by purified MnP from Phanerochaete chrysosporium. The results show that nitrogen-limited and high level of Mn²⁺ medium could obtain favorable MnP activity and inhibit the expression of lignin peroxidase by Phanerochaete chrysosporium. The purified MnP could transform 80% tetracycline in 3 h, and the threshold of reaction activator (H₂O₂) was about 0.045 mmol L⁻¹. After the 3rd cyclic run, the transformation rate was almost identical at the low initial concentration of TC (77.05–88.47%), while it decreased when the initial concentration was higher (49.36–60.00%). The antimicrobial potency of the TC transformation products by MnP decreased throughout reaction time. We identified seven possible degradation products and then proposed a potential TC transformation pathway, which included demethylation, oxidation of the dimethyl amino, decarbonylation, hydroxylation, and oxidative dehydrogenation. These findings provide a novel comprehension of the role of MnP on the fate of antibiotics in nature and may develop a potential technology for tetracycline removal.     

胶束及反胶束微环境中的槲皮素金属配合物

无机金属元素可与中药活性有机化合物通过配位键结合形成配合物,进而影响药物的生理活性[1]。但配合物的形成往往改变了原有机成分的溶解性能(如水溶性或脂溶性),而表面活性胶束体系可使金属有机配合物的水溶性或脂溶性得到明显改善,从而提高药物的生物利用度和改善药物的吸收。然而,胶束体系中已有的研究多是针对单纯的有机化合物[2]或生物分子如蛋白质[3]等,而涉及金属配合物胶束溶液的则很少,尤其是反胶束微环境中的中药金属配合物。反胶束亦称W/O型微乳液,是双亲物质在非极性有机溶剂中自发形成的具有纳米尺寸的含有水核的微小胶团聚集…     

十六烷基三甲基溴化铵逆胶束介质中邻氯代苯亚甲基丙二腈的化学发光测定

以十六烷基三甲基溴化烷 (CTMAB)在氯仿 环己烷为主体溶剂相中所形成的逆胶束介质 ,基于鲁米诺 H2 O2 化学发光体系对邻氯代苯亚甲基丙二腈 (CS)进行定量分析 ,详细研究了氯仿与环己烷的不同配比、R值 ([H2 O] [表面活性剂 ])、CTMAB浓度、pH值、鲁米诺浓度及H2 O2 浓度对化学发光强度的影响。CS的检测线性范围为 1× 10 - 5～ 5 .5× 10 - 3mol L ,检出限达 4× 10 - 6 mol L(S N =3) ,对水样及土样的回收率均在 90 %以上。     

硒代二半胱氨酸对白血病细胞系谷胱甘肽过氧化物酶的影响

观察了硒代二半胱氨酸对白血病细胞系（Ｕ９３７和Ｋ５６２）生长增殖和谷胱甘肽过氧化物酶的影响．结果表明，硒代二半胱氨酸抑制白血病细胞生长和增殖，其抑制作用与药物浓度呈正相关．经３．０μｍｏｌ／Ｌ（ＩＣ５０）硒代二半胱氨酸作用３天后（Ｕ９３７和Ｋ５６２白血病细胞内谷胱甘肽过氧化物酶活性显著提高（Ｐ＜０．０１），在培养第３天和第６天时无显著差别．谷胱甘肽过氧化物酶活性的提高有利于白血病细胞生长的抑制．     

Lignin Peroxidase from Streptomyces viridosporus T7A: Enzyme Concentration Using Ultrafiltration

It is well known that lignin degradation is a key step in the natural process of biomass decay whereby oxidative enzymes such as laccases and high redox potential ligninolytic peroxidases and oxidases play a central role. More recently, the importance of these enzymes has increased because of their prospective industrial use for the degradation of the biomass lignin to increase the accessibility of the cellulose and hemicellulose moieties to be used as renewable material for the production of fuels and chemicals. These biocatalysts also present potential application on environmental biocatalysis for the degradation of xenobiotics and recalcitrant pollutants. However, the cost for these enzymes production, separation, and concentration must be low to permit its industrial use. This work studied the concentration of lignin peroxidase (LiP), produced by Streptomyces viridosporus T7A, by ultrafiltration, in a laboratory-stirred cell, loaded with polysulfone (PS) or cellulose acetate (CA) membranes with molecular weight cutoffs (MWCO) of 10, 20, and 50 KDa. Experiments were carried out at 25 °C and pH 7.0 in accordance to the enzyme stability profile. The best process conditions and enzyme yield were obtained using a PS membrane with 10 KDa MWCO, whereby it was observed a tenfold LiP activity increase, reaching 1,000 U/L and 90% enzyme activity upholding.     

Mechanistic studies on the effect of veratryl alcohol on the lignin peroxidase catalyzed oxidation of pyrogallol red in reversed micelles

The lignin peroxidase (LiP) catalyzed oxidation of pyrogallol red (PR) in the absence and presence of veratryl alcohol (3,4-dimethoxybenzyl alcohol, VA) was carried out in bis (2-ethylhexyl) sulfosuccinate sodium (AOT)/ polyoxyethylene lauryl ether (Brij30) reversed micelles to elucidate the role of VA. Results indicated that VA could accelerate the LiP catalyzed oxidation of PR, especially at low H₂O₂ concentrations. Unlike in bulk aqueous medium, the protection of LiP by VA in the present medium was relatively unsubstantial, even at high H₂O₂ concentrations. Analysis of data from a series of experiments showed that the enhancement of the PR oxidation caused by VA was mainly due to the indirect oxidation of PR by VA^+∙ from the LiP catalyzed oxidation of VA. It was also found that at the same protector concentration (40 μM), VA (the physiological substrate of LiP) was less effective than PR (a phenolic compound) in protecting LiP from the H₂O₂ derived inactivation. This novel phenomenon deserves further study.      

聚苯胺纳米粒子的反胶束法合成及自组装

聚苯胺纳米粒子的反胶束法合成及自组装;聚苯胺;纳米粒子;反胶束;自组装     

AEOT反胶束中脂肪酶的催化活性

反胶束已广泛应用于膜模拟化学和蛋白质的液 液萃取中[1～ 3] ,反胶束酶反应作为实现有机相酶催化的方法之一 ,具有许多独特的优点 ,反胶束独特的结构特征使表面活性剂分子组成的膜将油水相隔开 ,从而有利于保持酶的活性和稳定性。酶在反胶束的微水环境中比在水溶液中更接近天然的细胞内环境 ,在这里酶和底物分子均可得到有效的分散 ,接触几率大大提高 ,因而催化效率也得到很大提高。反胶束可以适用于各种类型的 (亲水的、疏水的和双亲的 )底物[4] ,已逐步形成“胶束酶学”的研究分支 ,研究胶束酶学的Martinek等[3] 曾预言 :反胶束体系有可…     

Kinetic Studies on of Veratryl the Lignin Peroxidase Catalyzed Oxidation Alcohol by H2O2 in AOT/Isooctane/ Toluene/Water Reverse Micelles

The steady state kinetics of the lignin peroxidase （LIP） catalyzed oxidation of veratryl alcohol （VA） by H2O2 in a sodium bis（2-ethylhexyl） sulfosuccinate （AOT）/isooctane/toluene/water reverse micellar medium was studied and a comparison with the corresponding aqueous medium was made to understand the effect of the reverse micellar medium on the catalytic mechanism and kinetic parameters. Results indicated that the model reaction in the AOT reverse micelle followed the ping-pong mechanism with true kcat, Km,VA and KmH2O2 being 59.6min^-1, 13.9 mmol· L^-1 and 94.8 μmol·L^-1, respectively; inhibition of high level of H2O2 on LiP followed the reversible competitive pattern with Ki being 0.140 mmol·L^-1. The reaction mechanism and inhibition pattern in the AOT reverse micellar medium were the same as those in bulk aqueous medium, but the kinetic parameters except KmH2O2 were greatly different in the two media. The kcat and Ki values in the reverse micelle were approximately 2 and 20 times smaller than the corresponding values in the aqueous solution, but the Michaelis constant of VA was approximately 100 times greater than that in the aqueous solution. The above mentioned differences in the kinetic parameters were caused by the microheterogeneity and the interface of the AOT reverse micelle, which resulted in the partitioning of VA and H2O2, and by the changes of the conformation of LiP and the reactivity of the substrates.     

马来酸噻吗洛尔的CTAC逆胶束介导化学发光法测定

在酸性条件下,马来酸噻吗洛尔分子中氮原子被质子化后与阴离子AuCl4-形成离子缔合物,该缔合物被三氯甲烷带入鲁米诺的氯化十六烷基三甲基铵(cetyltrimethylammonium chlorine,CTAC)逆胶束中(三氯甲烷-环己烷(体积比3∶7)-H2O(0.3 mol.L-1Na2CO3缓冲溶液,pH11.5)),离解出来的AuCl4-立即与鲁米诺产生化学发光。在0.01~20 mg.L-1范围内,发光强度与马来酸噻吗洛尔的含量成线性关系,从而间接测定马来酸噻吗洛尔的含量。检出限(3δ)为0.5μg.L-1,对质量浓度为1.0 mg.L-1的马来酸噻吗洛尔进行11次平行测定,其RSD为1.8%。该法已成功用于片剂和滴眼液中马来酸噻吗洛尔的测定。     

新型阴离子表面活性剂的合成及其反胶束体系的酶催化性能

合成了未见文献报道的新型阴离子表面活性剂磷酸二[(2-乙基己氧基)乙基]酯钠(sodium di-[(2-ethylhexyloxy)ethyl] phosphate,DEEPA);以核磁共振氢谱和红外光谱表征了它的结构;在DEEPK/异辛烷反胶束体系中进行了脂肪酶催化橄榄油水解反应实验.结果表明,该反胶束体系的催化活性优于AOT反胶束体系,更优于油-水双相中的酶催化反应,最大活性是油-水双相体系的1.86倍.     

酚类聚合物在水相胶束中的酶促合成

本文报道辣根过氧化物酶在水相胶束中催化聚合取代酚类的研究。水相胶束中酶催化活力高，产物分子量均一；通过调节表面活笥剂和单体的浓度，可以有效地控制产物的分子量，从而建立了不同聚合度有机纳米材料酶促合成的新方法。产物具有较强的蓝紫色荧光及较好的耐热性能，是一种很有应用前景的蓝光材料。     

P204Li在有机相形成反向胶束过程的微量量热法研究

滴定微量量热法;P204Li在有机相形成反向胶束过程的微量量热法研究;热力学函数;临界胶束浓度;溶剂萃取;临界胶束浓度;     

Purification and Partial Characterization of Lignin Peroxidase from <Emphasis Type="Italic">Acinetobacter calcoaceticus</Emphasis> NCIM 2890 and Its Application in Decolorization of Textile Dyes

Lignin peroxidase was purified (72-fold) from Acinetobacter calcoaceticus NCIM 2890. The purified lignin peroxidase (55–65 kDa) showed dimeric nature. The maximum enzyme activity was observed at pH 1.0, between a broad temperature range of 50 and 70°C, at H₂O₂ concentration (40 mM) and the substrate concentration (n-propanol, 100 mM). Purified lignin peroxidase was able to oxidize a variety of substrates including Mn²⁺, tryptophan, mimosine, l-Dopa, hydroquinone, xylidine, n-propanol, veratryl alcohol, and ten textile dyes of various groups indicating as a versatile peroxidase. Most of the dyes decolorized up to 90%. Tryptophan stabilizes the lignin peroxidase activity during decolorization of dyes.     

Use of steam explosion liquor from sugar cane bagasse for lignin peroxidase production by Phanerochaete chrysosporium

The possibility of using two by-products of the sugar cane industry, molasses and bagasse steam explosion liquor (SEL), for lignin peroxidase (LiP) production by Phanerochaete chrysosporium was investigated. For comparison, the fungus was initially cultivated in synthetic media containing either glucose, sucrose, xylose, or xylan as sole carbon sources. The effect of veratryl alcohol (VA) was also investigated in relation to the enzyme activity levels. Results showed that sucrose was not metabolized by this fungus, which precluded the use of molasses as a carbon source. Glucose, xylose, and xylan promoted equivalent cell growth. Enzyme levels in the absence of VA were lower than 28 UI/L and in the presence of VA reached 109 IU/L with glucose and 85 IU/L with xylose or xylan. SEL was adequate for P. chrysosporium LiP production as LiP activity reached 90 IU/L. When VA was added to this medium, enzyme concentration increased to 155 IU/L.     

反向迁移毛细管胶束电动色谱分离测定复方丹参片中5种皂苷的含量

采用反相迁移毛细管胶束电动色谱方法分离测定了复方丹参片中人参皂苷Rd、Rb1、Rg1、Re和三七皂苷R1等5种皂苷的含量。考察了SDS、有机改性剂和磷酸浓度、样品溶剂及进样时间对样品分离和检测灵敏度的影响。最佳缓冲溶液组成为:10mmol/L磷酸-140mmol/LSDS-14%(V/V)乙腈-15%(V/V)异丙醇(pH=2.4),样品溶剂为20%甲醇-10mmol/LSDS,压力进样时间为12s。在最佳条件下,5种组分在27min内达到高效分离(柱效为1.1~1.6×106N/m),在一个数量级浓度范围内线性相关系数为0.9975~0.9993,日内和日间精密度分别小于4.8%和5.5%,回收率为96.5%~103.6%。该方法用于复方丹参片中皂苷类成分含量的测定,简单、快速、灵敏、准确。     

Self-Aggregation of Cationic Dimeric and Anionic Monomeric Surfactants with Nonionic Surfactant in Aqueous Medium

Spectrofluorometric measurements have been used to elaborate the self-aggregation of mixture of anioinic, sodium dodecylbenzenesulfonate (SDBS), and cationic gemini, alkanediyl-α, ω-bis (tetradecyldimethylammonium bromide) (14-4-14) with nonionic surfactant, polyoxyethylene 10 cetyl ether (Brij-56). The critical micelle concentration (cmc) of the binary mixtures has been investigated. Application of the regular solution theory (RST) to the experimental data yield the interaction parameter at mixed micelles (β), indicate an attractive interaction and reflect the synergistic behavior in both Brij-56/SDBS and Brij-56/14-4-14 systems. The micelle aggregation number (N _agg) was measured using a steady state fluorescence quenching method. The N _agg values of the mixed surfactant system were larger than those of pure components. The micropolarity of various combinations and the binding constants (K _sv) were determined from the ratio of intensity of peaks (I ₁/I ₃) of pyrene fluorescence emission spectrum and its quenching, respectively.     

丹参木质素及其单体含量的测定

本文建立了一种准确、快速的检测丹参中木质素及其单体含量的方法.采用Klason法和紫外分光光度法分别对丹参根和茎中酸不溶性木质素(Klason木质素)和酸溶性木质素含量进行了测定;运用硫代酸解法并结合气相色谱-质谱法(GC-MS)分别对丹参根和茎中各木质素单体组成进行了分析.结果显示,总木质素在丹参根和茎中的含量分别为...