光谱法研究铜锌超氧歧化酶与组氨酸钴(Ⅱ)的相互作用 Ⅲ.溶液的pH值、作用时间的影响

采用ＶＩＳ,ＩＣＰ 及酶活性测定等方法,研究铜锌超氧歧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）与组氨酸钴（Ⅱ） （Ｃｏ（Ｈｉｓ）ｎ ） 直接相互作用时溶液ｐＨ值、作用时间对此类相互作用的影响。结果发现,溶液的ｐＨ值越高,作用时间越长,越有利于此类相互作用的进行     

铜锌超氧化物歧化酶与色氨酸钴(Ⅱ)的相互作用

采用ＶＩＳ、ＩＣＰ及酶活性测定等方法,研究铜锌超氧歧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）与色氨酸钴（Ⅱ）（Ｃｏ（Ｔｒｐ）＾ｎ）的直接相互作用以及外加色氨酸钴（Ⅱ）的量、溶液ｐＨ值对此类相互作用的影响。结果发现：在水溶液中原酶活性中心处的Ｚｎ（Ⅱ）离子可被外加的色氨酸钴（Ⅱ）部分诱导、交换出来,而溶液中外加的Ｃｏ（Ｔｒｐ）＾ｎ中的Ｃｏ（Ⅱ进入酶的活性中心,形成“Ｃｏ－ＳＯＤ”酶衍生物,并相应影响了酶的催化活性     

可见吸收光谱法研究铜锌超氧歧化酶活性中心金属离子与氯化钴的相互作用

应用可见吸收光谱首次研究了铜锌超氧歧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）活性中心金属离子在一定缓冲溶液中与无机氯化钴的直接相互作用。讨论了加入不同比例量的氯化钴、不同的ｐＨ值、不同酸盐及作用的平衡时间对这种相互作用的影响。结果发现，ＣｏＣｌ２中的Ｃｏ（Ⅱ）与Ｃｕ２Ｚｎ２ＳＯＤ中的Ｚｎ（Ⅱ）有交换作用，形成部分的Ｃｕ２中的Ｃｏ２ＳＯＤ，且上述四种因素对此均有不同程度的影响。本研究开创了金属酶活性中心金属离子与外加无机金属化合物的直接相互作用的研究。     

可见吸收光谱法研究铜锌超氧化歧化酶活性中心金属离子与氯…

应用可见吸收光谱首次研究了铜锌超氧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）活性中心金属离子在一定缓冲溶液中与无机氯化钴的直接相互作用，讨论了加入不同比例量的氯化钴，不同的ｐＨ值，不同酸盐及作用的平衡时间对这种相互作用的影响，结果发现，ＣｏＣｌ２中的Ｃｏ（Ⅱ）与Ｃｕ２Ｚｎ２ＳＯＤ中的Ｚｎ（Ⅱ）有交换作用，形成部分的Ｃｕ２中的Ｃｏ２ＳＯＤ，且上述四种因素对此均有不同程度的影响，本研究开创了金属酶活性中心金属离子与外     

可见光谱法研究核酸酶P1与氯化铜(Ⅱ)的相互作用

首次采用ＶＩＳ与酶活性测定的方法,研究了溶液中核酸酶Ｐ１与无机氯化铜（Ⅱ）（ＣｕＣｌ２）的直接相互作用。结果发现：在水溶液中核酸酶Ｐ１活性中心的Ｚｎ（Ⅱ）离子可被外加氯化铜（ＣｕＣｌ２）中的Ｃｕ（Ⅱ）部分诱导、交换出来,而Ｃｕ（Ⅱ）进入酶的活性中心,形成相应“Ｃｕ（Ⅱ）－Ｐ１”酶衍生物,并随着溶液ｐＨ值的变化,形成酶的衍生物结构亦随之变化,相应地也影响了酶的催化活性。     

Mn（Ⅱ）,Co（Ⅱ）与HSA相互作用的荧光光谱研究

用荧光光谱法研究了生理ｐＨ和等离子点（ｐＨ＝５．３０）时Ｍｎ（Ⅱ）、Ｃｏ（Ⅱ）与ＨＳＡ的相互作用。根据Ｆｏｒｓｔｅ非辐射能量转移理论,得到了不同ｐＨ时Ｍｎ（Ⅱ）、Ｃｏ（Ⅱ）在ＨＳＡ中的第一强结合位置与Ｔｒｐ－２１４残基间的距离。这一结果远大于文献报道值,根据Ｍｎ（Ⅱ）、Ｃｏ（Ⅱ）在ＨＳＡ中的结合部位及ＨＳＡ的畴结构对这一显著差异进行了讨论。     

光谱法研究铜锌超氧歧化酶与组氨酸钴(Ⅱ)的相互作用 Ⅱ.外加组氨酸钴(Ⅱ)及磷酸盐的影响

采用ＶＩＳ和 ＩＣＰ及酶活性测定等方法,研究铜锌超氧歧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）与组氨酸钴（Ⅱ）［Ｃｏ（Ｈｉｓ）ｎ］ 的直接相互作用及外加组氨酸钴（Ⅱ）、磷酸盐对此类相互作用的影响。结果发现,水溶液中原酶活性中心的Ｃｕ（Ⅱ）和Ｚｎ（Ⅱ）离子可被外加的组氨酸钴（Ⅱ）部分诱导、交换出来,而Ｃｏ（Ｈｉｓ）ｎ 中的Ｃｏ（Ⅱ）进入酶的活性中心,形成“Ｃｏ－ＳＯＤ”酶衍生物各组分,并相应影响了酶的催化活性。与此同时,外加组氨酸钴（Ⅱ）及磷酸盐对此类相互作用有着重要的影响     

光谱法研究铜锌超氧歧化酶与组氨酸钴（Ⅱ）的相互作用：Ⅱ. …

采用ＶＩＳ和ＩＣＰ及酶活性测定等方法,研究铜锌超氧歧化酶（Ｃｕ２ＺｎＳＯＤ）与组氨酸钴（Ⅱ）〖Ｃｏ（Ｈｉｓ）〗的直接相互作用及外加组氨酸钴（Ⅱ）、磷酸盐对此类相互作用的影响。结果发现,水溶液中原酶活性中心Ｃｕ（Ⅱ）和Ｚｎ（Ⅱ）离子可被外加的组氨酸钴（Ⅱ）部分诱导,交换出来,而Ｃｏ（Ｈｉｓ）。中的Ｃｏ（Ⅱ）进入酶的活性中心,形成“Ｃｏ－ＳＯＤ”酶衍生物各组分,并相应影响了酶的催化活性。与此同时,外加     

光谱、波谱法研究铜锌超氧歧化酶与氯化钴(Ⅱ)、组氨酸钴(Ⅱ)相互作用

我们首次发现的铜锌超氧歧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）与氨基酸等发生直接相互作用的现象,是一种前人未研究过的重要的生化新现象［１］。在此新发现的基础上,本文用ＩＣＰ,ＶＩＳ,ＮＭＲ和酶活性测定等方法,又从不同角度拓展研究了Ｃｕ２Ｚｎ２ＳＯＤ酶与两类不同化合物,即无机氯化钴（ＣｏＣｌ２）、有机组氨酸钴（Ｃｏ（Ⅱ）（Ｈｉｓ）ｎ）的直接相互作用,发现酶活性中心金属离子同样与外加的这两类不同化合物发生相互作用,相应地影响了酶的催化活性。还发现Ｃｏ（Ⅱ）（Ｈｉｓ）ｎ比ＣｏＣｌ２与酶相互作用更强、更快,Ｃｏ（Ⅱ）（Ｈｉｓ）ｎ中的Ｃｏ（Ⅱ）更易进入酶中,更影响了酶的催化活性。     

溶剂浸渍滤纸的制备及其在XRFA中的应用研究（二）──XRFA中溶剂浸渍滤纸制样法研究

本文报道了Ｐ５０７溶剂浸渍滤纸（ＳＩＦＰ）的制备方法及应用溶剂浸渍滤纸富集金属离子制备适合Ｘ射线荧光光谱分析样片的方法。在ｐＨ３介质中制备了Ｌａ（Ⅲ），Ｃｅ（Ⅲ），Ｙｂ（Ⅲ）；在ｐＨ２．５的介质中制备了Ｔｈ（Ⅳ）；在２ｍｏｌ／ＬＨＣｌ介质中制备了Ｚｒ（Ⅳ）与Ｈｆ（Ⅳ）等元素的标准系列样片。本文报道了经ＸＲＦ测定的数据。各元素的检出限ＣＤＬ分别为Ｌａ：０．３１５μｇ（Ｌａ２Ｏ３）；Ｃｅ：０．３５９μｇ（ＣｅＯ２）；Ｙｂ：０．７０９μｇ（Ｙｂ２Ｏ３）；Ｔｈ：０．６２２μｇ（ＴｈＯ２）；Ｚｒ：０．６６６μｇ（Ｚｒ）；Ｈｆ：１．０８μｇ（Ｈｆ）。样片稳定时间约四个月。本文还对制备ＳＩＦＰ时滤纸的选择，制备样片时溶液通过ＳＩＦＰ的次数等方面进行了讨论。     

Spatially resolved solvent interaction with glassy HPMC polymers studied by magnetic resonance microscopy

Magnetic resonance microscopy was used to study the interaction of an alkaline water solvent (pH=12) with hydroxypropylmethyl cellulose (HPMC) matrices with different molecular masses Mw=12,000, 86,000, and 120,000. The polymers in the form of cylinders were hydrated at 37 degrees C and monitored at equal time intervals with a 300MHz Bruker AVANCE. The spatially resolved spin-spin relaxations times T2 and diffusion coefficients D of the solvent molecules within the gel layer of HPMC samples, along with changes in the dimension of the glass core of the polymers were determined as a function of hydration times. The experimental data allows us to characterize the diffusion mechanism as being Fickian and to determine the mean diffusivity values D of the solvent molecules for each voxel within the gel of the studied polymers. The influence of the molecular mass of the HPMC polymers on swelling properties has been shown.     

An interaction interpretation of special relativity theory. Part II

The interaction interpretation of special relativity theory (elaborated in Part I) is discussed in relation to quantum theory. The relativistic transformations (Lorentz processes) of physical variables, on the interaction interpretation, are observation-interaction dependent, just as are the physical values (eigenvalues) of systems described by quantum-theoretic state functions; a common, basic structure of the special relativity and quantum theories can therefore be presented. The constancy of the light speed is shown to follow from interaction-transformations of frequency and wavelength variables. A parallelism is suggested between, on the one hand, the Lorentz-Clausius distinction for relativistic transformations, and, on the other, the distinction between observation-dependent and observation-independent natural processes. The empirical study of rates of macroscopic clocks can provide a critical test of the interaction interpretation and of a possible extension to gravitational time changes; the role of time as prior determinant of natural process is at issue. The Hafele-Keating observations are of general relativity effects on clocks in accelerated motion.     

光谱,波谱法研究铜锌超氧歧化酶与氯化钴（Ⅱ）,组氨酸钴（？…

我们首次发现的铜锌超氧歧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）与氨基酸等发生直接相互作用的现象,是一种前人未研究过的重要的生化新现象。在此新发现的基础上,本文用ＩＣＰ,ＶＩＳ,ＮＭＲ和酶活性测定方法,又从不同角度拓展研究了Ｃｕ２Ｚｎ２ＳＯＤ酶与两类不同化合物,     

The effect of the pH on the interaction of L‐arginine with colloidal silver nanoparticles. A Raman and SERS study

Raman and surface enhanced Raman scattering (SERS) spectroscopies were used to study the pH effect (7 to 9) on the interaction of arginine (Arg) with colloidal Ag nanoparticles (AgNps). A new methodology was implemented in order to obtain reproducible SERS spectra in solution. The dependence of the Arg concentration on the stability of the AgNps is discussed. A pH increasing of the colloidal solution to the limits of the Arg pKa₂ value induces a preferential and stable Arg–metal interaction. ξ potential measurements of the Arg–AgNps system at different pH conditions studied provide information about the Arg–AgNps interaction; the pH increasing favors the interaction. SERS spectra at pH 7 indicate that the molecule interacts with the Ag surface only through the guanidinium fragment. By increasing the pH to 9, the molecule adopts a new conformation on the surface; the metal–analyte interaction is verified through the guanidinium, carboxylate and the aliphatic moieties. In addition, theoretical calculations performed by using the extended Hückel method for a model of Arg interacting with an Ag surface support the observed SERS results. Copyright © 2013 John Wiley & Sons, Ltd.     

Immobilization of glucose oxidase using CoFe2O4/SiO2 nanoparticles as carrier

Aminated-CoFe₂O₄/SiO₂ magnetic nanoparticles (NPs) were prepared from primary silica particles using modified StÖber method. Glucose oxidase (GOD) was immobilized on CoFe₂O₄/SiO₂ NPs via cross-linking with glutaraldehyde (GA). The optimal immobilization condition was achieved with 1% (v/v) GA, cross-linking time of 3 h, solution pH of 7.0 and 0.4 mg GOD (in 3.0 mg carrier). The immobilized GOD showed maximal catalytic activity at pH 6.5 and 40 °C. After immobilization, the GOD exhibited improved thermal, storage and operation stability. The immobilized GOD still maintained 80% of its initial activity after the incubation at 50 °C for 25 min, whereas free enzyme had only 20% of initial activity after the same incubation. After kept at 4 °C for 28 days, the immobilized and free enzyme retained 87% and 40% of initial activity, respectively. The immobilized GOD maintained approximately 57% of initial activity after reused 7 times. The K_M (Michaelis-Menten constant) values for immobilized GOD and free GOD were 14.6 mM and 27.1 mM, respectively.     

Spectrophotometric studies on the interaction between myricetin and lysozyme in the absence or presence of Cuor Fe

The binding of myricetin to lysozyme (Lys) in aqueous solution was investigated by fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy (UV) and circular dichroism (CD) spectra under physiological conditions. There are also many metal ions present in body, thus the research about the effect of metal ions on the interaction of drugs with proteins is crucial. In this study, we have investigated the effect of both familiar metal ions Cu²⁺ and Fe³⁺ on the interaction between myricetin and Lys by using spectroscopy technique at pH 7.40, for the first time. Spectrophotometric observations are rationalized in terms of a static quenching process in a static quenching way. The cause of showing upward curvy patterns in Stern-Volmer plots was analyzed. The binding constants and binding sites of myricetin with Lys with or without Cu²⁺ and Fe³⁺ at different concentrations of myricetin were calculated. UV/vis measurements on the enzymatic activity of Lys with or without Cu²⁺ in the absence or presence of myricetin indicated that the interaction between myricetin and Lys led to a reduction in the activity of Lys. Furthermore, the effect of pH on the binding constant of myricetin with Lys was also examined.     

ESR Study in Reactive Oxygen Species Free Radical Production of Pinus kesiya var. langbianensis Heartwood Treated with Laccase

Enzymatic oxidation of lignin phenolic hydroxyl groups can enhance the level of autoadhesion between wood fibers or particles depending upon the bonding mechanism of wood-based materials without synthetic adhesives such as urea and phenol formaldehyde. The adhesive effect is caused by an increased number of reactive oxygen groups at the fiber surface. The parameters of laccase-treated wood fibers play vital roles in generating reactive oxygen species (ROS) free radicals. Laccase I (white-rot fungi) and laccase II (Aspergillus sp.) are used to catalyze the oxidation of heartwood powder of Pinus kesiya var. langbianensis in suspension under different pH values, temperatures, treatment times and different laccase concentrations. Electron spin resonance spectroscopy and spin trapping technique were used to detect the ROS free radicals generated in the laccase-treated heartwood powder and it was found that in it the concentration of ROS free radicals was higher than that in the control. Analysis of variance indicates that there was a significant difference between the ROS concentration values of laccase-treated heartwood powder under different pH values, treatment temperatures and times, and laccase dosages for both laccase I and II. Furthermore, the concentration of ROS free radicals generated by laccase I is higher than that generated by laccase II. It was found that the optimum conditions for generation of ROS in laccase-treated heartwood powder by the two kinds of laccase are pH 3.0; treatment temperature, 50 °C; treatment time, 2 h; enzyme concentration, 20 units/g of wood powder. Authors' address: Xinfang Duan, Research Institute of Wood Industry, Chinese Academy of Forestry, Wan Shou Shan, Beijing 100091, People's Republic of China     

Nuclear magnetic relaxation by spin-rotation interaction.

Spin-rotation interaction constants, c, are calculated from the paramagnetic term of the nuclear magnetic shielding constant, σ _p, using a relationship originally due to Ramsey. Calculated values show excellent agreement with experimental determinations from molecular beam measurements. Since σ _p can be easily estimated from the chemical shift of the nuclear resonance this provides a general method for estimating spin-rotation interaction constants.

Chemical shift anisotropies allow the components c _⊥ and c _‖ of the spin-rotation interaction tensor to be determined. Generally both components have the same sign and are of similar magnitude. The r.m.s. value of the spin-rotation interaction constant, required to calculate nuclear spin-lattice relaxation times, is not expected to differ appreciably from average values obtained from molecular beam measurements or magnetic shielding.

Values for the molecular angular velocity correlation time, τ _sr, calculated directly from nuclear spin-lattice relaxation times are about a factor of four longer than those predicted by the relationship between τ _sr and the re-orientation correlation time, τ _d, as given by Hubbard.