鉴定合成副产物和确定活性物质的对映体组成以及制剂中存在的杂质，是法医和药理学分析的重要目的。 这对于比较和评价生产方法也是有用的。 在本应用中，我们将展示CD在对映体组成测定中的适用性。

This application notes demonstrates the use of the J-1500 CD spectrometer and ATS-530 automatic titrator to monitor the interaction of HSA titrated with 3,5-diiodosalicylic acid. While 3,5-diiodosalicylic acid is achiral, its interaction with chiral HSA induces circular dichroism.

This application note demonstrates that stopped-flow CD measurements can be used to measure the protein unfolding processes, analyze the secondary structure changes, and obtain reaction rate constants

这个应用文章主要将演示缓解和一滴血微量试样光盘通过测量的效率四个蛋白的CD光谱。

This application note monitors the existence of an intermediate state by probing the refolding of denatured cytochrome c using a JASCO CD spectrometer and the SFS-492 Stopped-Flow system.

Circular dichroism spectroscopy (CD) is very sensitive to the secondary structure of polypeptides and proteins. Circular dichroism is a form of light absorption spectroscopy that measures the difference in absorbance of rightand left-circularly polarized light (rather than the commonly used absorbance of isotropic light) by a substance. It has been shown that CD spectra between 260 and approximately 180 nm can be analyzed for the different secondary structure types: alpha helix, beta sheet, beta turn, random coils, etc. Secondary structure determination by CD is reported to achieve accuracies of 0.97 for helices, 0.75 for beta sheet, 0.50 for turns, and 0.89 for other structure types. In this application CD will be used to follow the denaturation of myoglobin during an automated pH titration with acid.

An emission line of light source such as a sodium lamp or a mercury lamp is usually used to measure the optical rotation of pharmaceutical products. However, the Japanese Pharmacopeia and the European Pharmacopeia only mention the use of a sodium lamp as the light source. A polarimeter using a halogen lamp and a band pass filter (BPF) can also be used, as mentioned in the United States Pharmacopeia. However, the measurement error from the transmission property, that is the difference between the center wavelength of the BPF and the wavelength of emission line, cannot be avoided. Herein, the optical rotation of pirarubicin was measured using a sodium lamp and a halogen lamp, and the measurement error between the results was evaluated.

Optical rotation is the property of substances, rotating the plane of polarization when linearly-polarized light passes through such substances. This is the property which occurs specifically to optical active substances in which the refractive indices of right and left circularly-polarized light are different. Optical rotation that rotate light in a clockwise direction as viewed towards the light source is defined as dextrorotation (+) and the opposite, levorotation (-).

Optical rotation of Dextromethorphan Hydrobromide in accordance with the U.S. Pharmacopeia, is requested to be measured at 325 nm, however there is no emission line of 325 nm available in the polarimeter using Na lamp or Hg lamp as light source. Therefore, for the measurement of optical rotation of Dextromethorphan Hydrobromide, a polarimeter with halogen lamp as a light source and interference filter (325 nm) has been usually used, but as shown in Fig. 1, the optical rotatory dispersion (ORD) spectrum, there is a very steep slope in the short wavelength range near 325 nm, where even a very small error in the wavelength of interference filter may cause a very large error in the optical rotation measurement, which will makes the accurate measurements very difficult. On the other hand, if the measurement by using 365nm is allowed, since no wavelength error is expected, the measurement of optical rotation can be implemented with much higher accuracy. In this experiment, Dextromethorphan Hydrobromide was measured using polarimeter with Hg lamp (365 nm), polarimeter with Halogen lamp and interference filter (325 nm) and polarimeter with ORD attachment.

The function of a protein or peptide is closely related to its structure. Since CD measurements probe amino acid structure changes, CD is widely used for the structural analysis of protein and peptide molecules formulated for pharmaceutical use. CD spectral shapes reflect the abundance ratio of secondary structure motifs in proteins and poly-peptides and secondary structure analysis of CD data provides a fast and accurate indication of change in these structures.

This application note demonstrates how to determine a sample’s excitation and emission maxima for obtaining more indepth fluorescence measurements using the 3-D Fluorescence Measurement Program.

The functionalities of chiral compounds have been studied for the development of advanced molecules for many applications. The study of chiral compounds has spread to several fields such as natural products, pharmaceuticals and other functional molecules, and it can be pointed out that among those studies, the structural analysis of chiral compounds is a very important topic. X-ray Diffraction (XRD), Nuclear Magnetic Resonance (NMR) and Electronic Circular Dichroism (ECD) using UV/Vis light are employed as primary methods for the structural analysis of chiral compounds. In this paper, the measurement of chiral compounds by Vibrational Circular Dichroism (VCD) using infrared light will be outlined.

This application note demonstrates the measurement and analysis of camphorquinone using two complimentary techniques: circular dichroism and circularly polarized luminescence.

Fluorescence detection has been widely used as one of a practical detection method in HPLC analysis. It enables the selective detection of fluorescent substances, with sensitivity that can be up to 1000 times greater than with UV detection.

This application note illustrates temperature-dependent CD and fluorescence measurements of lysozyme obtained simultaneously using the J-1500 CD spectrometer, FMO-522 Emission Monochromator accessory, and Temperature/Wavelength Scan Measurement program.

Atmospheric water vapor and carbon dioxide (CO2) strongly absorb in the infrared region and can interfere with the analysis and detection of weak sample peaks due to the additional peaks in the spectrum. In order to reduce the effect of the background peaks associated with H20 and CO2 it is important to maintain the concentration of water vapor and CO2 at the same level when measuring both the background and sample. In this application note, we would like to introduce a couple measurement options to minimize the effects of CO2 and water vapor, including “Shuttle Measurement” and “Purge and Vacuum”.

This application note demonstrates the high resolution CPL spectrum measurements of europium tris[3-(trifluorometh ylhydroxymethylene)-(+)-camphorate] (Eu(facam)3) using a CPL-300. Eu(facam)3 is a common NMR shift reagent and has been used as a standard for CPL measurements.2

绿色荧光蛋白(GFP)是一种在紫外光照射下发出绿色荧光的蛋白质。此应用说明 用CPL-300和J-1500分别获得了gfp的cpl和cd光谱。

本应用说明了如何使用圆二色的光谱质控软件监测HSA的生物分子稳定性，并突出了光谱质控测试程序的特点。

由于自动测量系统具有自动分析多个样品的能力，节省了时间和人力，越来越受到制药企业的重视。本文介绍了一种使用高通量圆二色光谱仪自动测量多个蛋白质样品的方法。

随着核磁共振和X射线结晶学的发展，圆二色谱是蛋白质结构分析中不可缺少的一种测量方法.对于CD样品的测量，小体积或低浓度是典型的要求，JASCO开发了一种新的采样技术来满足这些样品的要求。 此应用通过测量四种蛋白质的圆二色光谱来说明一滴微取样盘的简易性和有效性。

本应用介绍了如何使用圆二色光谱仪（CD）的多元SSE程序分析八种蛋白质的二级结构，并与x射线晶体学得到的二次结构结果吻合较好。

Human serum albumin (HSA) is the most abundant protein in blood plasma. HSA binds with pharmaceutical compounds and other in-vivo substances and plays an important role in the transport of these substances to target organs. Several studies have reported on the binding affinity of HSA and its interactions with a variety of compounds.