基于可见吸收信号的乳酸脱氢酶光纤传感器

报道一种测定乳酸脱氢酶活力的基于可见吸收信号的光纤生物传感器，在该传感体系中，通过辅酶Ｉ的氧化还原对（ＮＡＤ＾＋／ＮＡＤＨ）将乳酸脱氢酶和心肌黄酶催化的两个脱氢过阳以耦合，第一个脱氢过程对分析对象进行了化学识别，第二个脱氢过程引起可见吸收信号的变化，该传感器对０～４００Ｕ／Ｌ的乳酸脱氢酶有线性响应关系，检测下限为４８ＵＬ，该传感器已用于人体血清中乳酸脱氢酶活力的测定。     

光声量热法测定辅酶B12的光解量子产率

时间可分辨的光声最热法（Time－resolvedphotoacousticcalorimetry；简称PAC）是研究脉冲激光诱发的快速光化学和光生物化学反应过程动力学和热力学信息的一种有效方法[1－5]。本文采用压电陶瓷圆管同时作为样品油和换能器组成的PAC探测系统[6]，以波长λ＝355nm的脉冲激光（脉冲宽度8ns，脉冲重复频率10Hz）为光源激发辅酶B12甲醇溶液；研究其解量子产率，获得了满意的结果．1实验被测溶液注入两端用石英玻璃封口的压电陶瓷圆管内腔，激光束透过石英窗照射溶液（如图］所示）为标定被测样品的非辐射放热量，利用能在极短的时间内（＜l…     

Crystal Structure Investigations of Inclusion Complexes Between β-cyclodextrin and Alkyl(aqua)cobaloximes (Alkyl=Butyl,Hexyl and Cyclohexyl)

The crystal and molecular structures of alkylcobaloxime/ g -cyclodextrin ( g -CD) inclusion complexes: butyl(aqua)cobaloxime/ g -CD ( 1 ). hexyl(aqua)cobaloxime/ g -CD ( 2 ) and cyclohexyl(aqua)cobaloxime/ g -CD ( 3 ) were determined by X-ray diffraction analyses. Crystal data for 1 14H 2 O: P 2 1 2 1 2 1 , a =15.1335(3), b =18.9630(2), c =28.1545(5) Å, Z =4; 2 12H 2 O: P 2 1 2 1 2 1 , a =15.1135(4), b =19.1477(5), c =28.2715(7) Å, Z =4; 3 10H 2 O: P 2 1 2 1 2 1 , a =15.6898(2), b =16.9094(2), c =28.9762(2) Å, Z =4. The structural and conformational comparisons for the three g -CD inclusion complexes with their guest molecules as well as other CD inclusion analogs are discussed.     

含辅酶Q10材料的抗辐射性能及含量测定

采用高效液相色谱法测定了辅酶Q10(CoQ10)的含量,并探讨了CoQ10的防晒性能.色谱柱为Kromasil 5-C18柱(150×4.6 mm,5μm);流动相为甲醇-无水乙醇(体积比30:70),流速为1.0 mL/min;检测波长275 nm.实验考察了不同含量CoQ10在3个紫外区的防晒性能,及与维生素C或维...     

Inclusion Complexes of Coenzyme Q10 with Polyamine‐Modified β‐Cyclodextrins: Characterization,Solubilization, and Inclusion Mode

The inclusion‐complexation behavior of coenzyme Q10 (CoQ10) with the three polyamine‐modified β‐cyclodextrins (CDs) 1 – 3 was investigated in both solution and the solid state by means of NMR, XRD, and FT‐IR spectroscopy. The results showed that the apparent solubility of CoQ10 increased linearly upon addition of hosts 1 – 3 , giving A_L‐type phase‐solubility curves. These hosts 1 – 3 were able to solubilize CoQ10 to high levels, up to 1.35, 1.52, and 1.44 mg/ml (calculated as CoQ10), respectively. The host 2 with a moderate‐length chain is the most suitable for inclusion complexation of CoQ10. Accroding to the ROESY experiments, the MeO groups of CoQ10 and the tether of 2 can be co‐included into the cavity of β‐CD through the induced‐fit interaction between host and guest. The binding ability of modified β‐CDs 1 – 3 upon complexation with CoQ10 are discussed from the viewpoints of the size/shape‐matching relationship and the induced‐fit concept between host CDs and guest CoQ10 molecule.     

Spectrofluorimetric determination of trace amount of coenzyme II using ciprofloxacin-terbium complex as a fluorescent probe

A new spectrofluorimetric method was developed for the determination of trace amount of nicotinamide adenine dinucleotide phosphate (NADP). Using terbium ion (Tb³⁺)-ciprofloxacin (CIP) complex as a fluorescent probe, in the buffer solution of pH=9.00, NADP can remarkably enhance the fluorescence intensity of the Tb³⁺-CIP complex at and the enhanced fluorescence intensity of Tb³⁺ ion is in proportion to the concentration of NADP. Optimum conditions for the determination of NADP were also investigated. The dynamic range for the determination of NADP is 4.9×10⁻⁷−3.7×10⁻⁶ mol L⁻¹ with detection limit of 1.3×10⁻⁷ mol L⁻¹. This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of NADP in synthetic water samples. Moreover, the enhancement mechanisms of the fluorescence intensity in the Tb³⁺-CIP system and the Tb³⁺-CIP-NADP system have been also discussed.     

Two Dimensional 1HNMR Studies on 2′5′-Dideoxyadenosylcobalamin

The ¹HNMR spectrum of 2′,5′-dideoxyadenosylcobalamin, a Coenzyme B₁₂(5′-deoxyadenosylcobalamin) analogue, has been assigned by 2D COSY. Its proton coupling constants have also been measured by J-resolved experiment. The comparison between the analogue and Coenzyme B¹² was made.     

Voltammetric determination of coenzyme Q10 in pharmaceutical dosage forms

A simple and rapid voltammetric method has been developed for the quantitative determination of coenzyme Q(10) (CoQ(10)) in pharmaceutical preparations. Studies with differential pulse voltammetry (DPV) were carried out using a glassy carbon electrode (GCE) in a mixed solvent containing 80 vol.% acetic acid and 20 vol.% acetonitrile. A well-defined reduction peak of CoQ(10) was obtained at -20 mV vs. Ag/AgCl. The voltammetric technique applied provides a precise determination of CoQ(10) using the multiple standard addition method. The statistical parameters and the recovery study data clearly indicate good reproducibility and accuracy of the method. The accuracy of the results assessed by recovery trials was observed to be within the range of 101.1% to 102.5%. The detection and quantification limits were found to be 0.014 mM (12 mg L(-1)) and 0.046 mM (40 mg L(-1)), respectively. An analysis of real samples containing CoQ(10) showed no interferences with common additives and excipients, such as unsaturated fatty acids and soya lecithin. The method proposed does not require any pretreatment of the pharmaceutical dosage forms. A spectrophotometric determination of CoQ(10) in real samples diluted in mixtures containing ethanol and n-hexane was also performed for comparison.     

An optimized luciferase bioluminescent assay for coenzyme A

A new bioluminescent method for coenzyme A (CoA) quantification is described. It is based on the enzymatic conversion of dehydroluciferyl-adenylate (L-AMP) into dehydroluciferyl-coenzyme A (L-CoA) by firefly luciferase (E.C. 1.13.12.7) (LUC), which causes a flash of light that can be measured in a luminometer. The method was subjected to optimization using experimental design methodologies to obtain optimum values for the concentrations of L-AMP ([L-AMP]), luciferase ([LUC]), ATP ([ATP]) and luciferin ([LH₂]). This method has a linear response over the range of 0.25–4 μM of CoA, with a limit of detection (LOD) of 0.24 μM and a limit of quantification (LOQ) of 0.80 μM. The assay has a relative standard deviation of about 7%. By coupling this optimized procedure to bioluminescent detection, a sensible and robust method can be obtained for the analysis of CoA.     

ATP-Independent and Cell-Free Biosynthesis of β-Hydroxy Acids Using Vinyl Esters as Smart Substrates

In vitro biosynthetic pathways that condense and reduce molecules through coenzyme A (CoASH) activation demand energy and redox power in the form of ATP and NAD(P)H, respectively. These coenzymes must be orthogonally recycled by ancillary reactions that consume chemicals, electricity, or light, impacting the atom economy and/or the energy consumption of the biosystem. In this work, we have exploited vinyl esters as dual acyl and electron donor substrates to synthesize β-hydroxy acids through a non-decarboxylating Claisen condensation, reduction and hydrolysis stepwise cascade, including a NADH recycling step, catalyzed by a total of 4 enzymes. Herein, the chemical energy to activate the acyl group with CoASH and the redox power for the reduction are embedded into the vinyl esters. Upon optimization, this self-sustaining cascade reached a titer of (S)-3-hydroxy butyrate of 24 mM without requiring ATP and simultaneously recycling CoASH and NADH. This work illustrates the potential of in vitro biocatalysis to transform simple molecules into multi-functional ones.