甲醇对微过氧化酶-11电化学行为的影响

用电化学和圆二色性 (CD)光谱方法比较了不含和含质量分数为 2 0 %甲醇的微过氧化物酶 -1 1 (MP-1 1 )溶液的电化学和电催化性能及结构的差别 .发现加入甲醇使 MP-1 1的电化学反应的可逆性和对 H2 O2 还原的电催化活性增加 ,这是由于加入甲醇使部分双聚的 MP-1 1分子变成单体分子 ,分子的 α-螺旋和 β-转角的结构含量增加 ,无规卷曲的结构含量降低 ,MP-1 1分子中血红素的暴露程度增加而引起的.

Promoter effect of La3+ on the electrochemical reaction of microperoxidase-11

The effect of La3+ on the electrochemical behavior and structure of heme undecapeptide-microperoxidase-11 (MP-11)-in the aqueous solution was investigated using cyclic voltammetry, circular dichroism (CD) and UV-vis absorption spectrometry. It was found for the first time that La3+ would promote the electrochemical reaction of MP-11 at the glassy carbon (GC) electrode. This is mainly due to the fact that La3+ would induce more beta-turn and alpha-helical conformations from the random coil conformation of MP-11 and increase the non-planarity of the heme.

Surface-enhanced Raman spectroscopy of microperoxidase-11 on roughed silver electrodes

The conformation of microperoxidase-11 (MP-11) adsorbed on roughened silver electrodes was studied using surface-enhanced Fourier transform Raman spectroscopy. The results demonstrate that MP-11 was initially adsorbed via its polypeptide chain with a alpha-helix conformation, as indicated by the enhancement of the characteristic bands related to the amides I and III. The weak resonance effect of the porphyrin macrocycle in the near IR region contributes to the spectrum of the heme group. The presence of imidazole as the sixth ligand to the heme iron influences the conformation of the polypeptide chain of MP-11 on the electrode surface. Evaporation of solvent water results in an opened conformation of the adsorbed MP-11. which allows the heme group to contact the electrode surface directly.

金电极表面聚赖氨酸固定微过氧化物酶-11的电化学研究

通过聚赖氨酸修饰将微过氧化物酶 -11 ( MP-11 )固定在金电极表面,制备成 MP-11修饰电极.修饰在电极表面上的 MP-11的血红素活性中心与电极之间可进行直接的电子传递反应,其氧化还原式电位为-0.39V.该修饰电极对氧的还原具有电催化活性.当 MP-11与咪唑发生轴向配位反应时,其氧化还原式电位发生负移,此时对氧的还原不再具有电催化活性.

Crystal structure of 11-{[(4 '-heptoxy-4-biphenylyl) carbonyl]oxy}-1-undecyne

The crystal structure of 11-{[(4'-heptoxy-4-biphenylyl) carbonyl] oxy}-1-undecyne (A9EO7), an acetylene with a biphenyl mesogenic moiety, was studied by combination of electron diffraction (ED), wide-angle X-ray diffraction (WAXD), and molecular simulation of ED pattern and molecular packing. A9EO7 was found to adopt an orthorhombic P2(1)2(1)2 space group with cell parameters of a = 5.78 Angstrom, b = 7.46 Angstrom, and c = 63.26 Angstrom, for which molecular packing calculations were conducted to elucidate the molecular conformation. Its crystal morphology was observed using a transmission electron microscope (TEM) and an atom force microscope (AFM). A9EO7 crystal grew to form step like morphology. Crystallization behavior of A9EO7 in magnetic field was examined. Induced by magnetic field A9EO7 could crystallize in such a way that its molecular long axis was parallel to the substrate.

Electrochemical and electrocatalytic properties of microperoxidase-11 adsorbed on the poly-L-lysine modified Ag electrode

It is found that Ply adsorbed roughed silver electrode, it is easy to immobilize MP-11 with the electrostatic interaction and to prepare the MP-11/Ply/Ag modified electrode. The preparation method of the modified electrode is simple. In addition, the modified electrode obtained shows the high and stable electrocatalytic activity for O-2 reduction. It is also found that when the sixth coordination of heme in MP-11 is replaced with other coordination species with stronger coordination ability, such as imidazole, its formal redox potential shifts to the negative direction and the electrocatalytic activity for O-2 reduction is reduced.

高真空强静电场对熔融结晶尼龙-11晶体结构的影响

使用 XRD法研究了在高真空不同强度静电场下熔融结晶尼龙 - 11的晶体结构。实验发现 ,随静电场强度的增大 ,尼龙 - 11的晶格参数增大 ,且尼龙 - 11由 α型逐渐向 δ′型转变

炭载微过氧化物酶-11电极对O_2和H_2O_2还原的电催化性能

通过平衡吸附法将微过氧化物酶 -1 1 (MP-1 1 )沉积到活性炭上制成 MP-1 1 /C催化剂 ,利用循环伏安法、线性扫描法和旋转圆盘电极技术研究了该催化剂对 O2 和 H2 O2 的电催化还原 .结果表明 ,MP-1 1 /C对 O2和 H2 O2 的电化学还原均具有较好的催化活性 ,并且氧的还原机理与溶液 p H值有关 ,为生物燃料电池的研制提供了一种较好的酶固定方法和一种比较有希望的氧还原催化剂

微过氧化酶-11在聚赖氨酸修饰银电极上的电化学及电催化

发现利用吸附在粗糙Ag电极上的聚赖氨酸(Ply),以静电作用方式固定微过氧化酶-11(MP-11)来制备MP-11/Ply/Ag修饰电极,不但方法简单,而且制得的修饰电极对O2的还原有高的电催化活性和好的稳定性.另外还发现MP-11分子中血红素的第六配体被配位能力较强的配体,如咪唑取代时,其本身的氧化还原电位负移,对O2还原的电催化活性降低.

Crystal structure and variation in unit cell parameters with crystallization temperatures of poly (ether ketone ether ketone ketone)s containing meta-phenyl links (PEKEKmK)

The X-ray diffraction patterns of the crystalline aromatic ketone polymer PEKEKmK (aryl ether ketone ether ketone ketone polymer containing meta-phenyl links) have been investigated (for the chemical structure, see Formula). An orthorhombic unit cell is proposed to contain two chains with a = 0.772 nm, b = 0.604 nm and c = 2.572 nm. According to the orthorhombic system, the 11 reflections of this polymer were indexed. Meanwhile, variation in unit cell parameters with crystallization temperatures of PEKEKmK was also investigated. [GRAPHICS]

Determination of ascorbic acid by flow injection chemiluminescence suppression method

chemiluminescence suppression method for the determination of ascorbic acid based on Luminol-KIO4-H2O2-ascorbic acid system was established. The linear range for ascorbic acid is 1.0 x 10(-7) similar to 1.0 x 10(-5) mol/L and the detection limit is 6.0 x 10(-8) mol/L. The relative standard deviation (n = 11) is 1.0% for 8.0 x 10(-7) mol/L ascorbic acid. The method has been used to determine the content of ascorbic acid in tablets and injections with satisfactory results.

Resolution of 3,3 '-dioxo-1,1 '(3H,3 ' H)spirobi[isobenzofuran]-5,6,5 ' 6 '-tetracarboxylic acid and Optically active Polyimides thereof

3,3'-Dioxo-1.1'(3H.3'H)spirobi[isobenzofuran]-5,6,5',6 acid 1 was resolved successfully and the corresponding optically active polyimides PI were synthesized. The properties of the optically active PI and the racemic one were investigated. The results showed that the specific rotation of(-)-PI was about two times to that of the: (+)-PI, and the regularity of the optically active PI was higher than that of the racemic one.

Valence of elements in HgBa2Can-1CunO2n+2+delta (n=1, 2, 3, 4)

Valence of elements in HgBa2Can-1CunO2n+2+delta (n=1, 2, 3, 4) (both argon and oxygen annealed samples) were calculated. The result indicated for both argon and oxygen annealed samples, Hg had the lowest valence for the highest T-c sample. For fixed n, the valence of Cu in oxygen annealed samples was larger than that in argon annealed samples, indicating that oxygen annealed samples produce more carriers than argon annealed samples.

Infrared and MAS NMR spectroscopic studies of Al18B4O33

The IR spectrum and B-11 and Al-27 MAS NMR spectra of Al18B4O33 are presented and discussed in relation to the possible existence of boron atoms substituting for aluminum atoms. The IR spectrum shows that the strong vibrations of the BO3 groups are present in the 1 500 similar to1 200 cm(-1) region, and very weak bands of BO4 units art present in the region from 1 000 to 1 100 cm(-1). B-11 MAS NMR spectrum indicates that the strong signal for BOB units appears in the region from delta +5 to delta +20, and the very weak signal for BO4 units is at about delta -1, while Al-27 MAS NMR spectrum shows five peaks at about delta +62, +42.1, +14, -4.7 and -6.4, originating from AlO4, AlO4, AlO5, AlO6 and AlO6, respectively, These results reveal that there are minor BO4 units in Al18B4O33, indicating that a small amount of B atoms substitute for Al atoms in the 4-fold coordination.

Fabrication and electrochemical behaviors of multilayers composed of heteropholyanions and poly(diallyldimethylammonium chloride) on 4-aminothiophenol modified gold electrodes

Multilayer films composed of heteropolyanions (HPAS, SiMo11 VO405-) and cationic polymer poly(diallyldimethylammonium chloride) on 4-aminothiophenol self-assembled-monolayer were fabricated by electrochemical growth. Growth processes of the composite films were characterized by cyclic voltammetry. The results prove the third redox peak of Mo increases more rapidly, otherwise the other Mo redox peaks increase very slowly when the number of layers of heteropolyanions is greater. The peak potentials of composite films shift linearly to negative position with higher pH, which implies that protons are involved in the redox processes of HPA. The investigation of electrocatalytic behaviors of composite films shows a good catalytic activity for the reductions of HNO2 and BrO3-. Catalytic currents increase with increasing number of layers of heteropolyanions, moreover, the catalytic currents have a good linear relationship with the concentrations of BrO3-.