Publisher Summary This chapter provides an overview of the 13 Carbon-nuclear magnetic resonance ( 13 C-NMR) spectroscopy of monosaccharides. The 13 C-NMR spectroscopy has become increasingly important as a tool for the characterization and structural elucidation of sugars and their derivatives. Although 13 C-NMR is closely related to 1 H-NMR spectroscopy, especially when both types of spectra are recorded with Fourier-transform instruments, the two techniques are sufficiently different to be valuable complements to each other. In many cases, in particular when dealing with complex molecules such as polysaccharides, the amount of information obtainable from 1 H-NMR spectra is limited as compared to that revealed by 13 C- NMR spectra. This chapter provides an almost complete collection of 13 C- NMR chemical shifts of monosaccharides, their methyl glycosides, and acetates, along with the examples of shift data for as many different types of monosaccharide derivative as possible. It also provides details on sampling techniques and assignment techniques, and discusses the identity of monosaccharides, their structure determination, and conformational analysis .

Carbon-13 Nuclear Magnetic Resonance Spectroscopy of Monosaccharides

Solvent suppression in Fourier transform nuclear magnetic resonance

The introduction of Fourier transform methods has not only remarkably enhanced the sensitivity of high-resolution NMR spectroscopy, thus allowing measurements to be made on less sensitive nuclei of the Periodic Table, but also has paved the way for the development of a large number of new experimental techniques. On the one hand, procedures already known have been improved and can now be performed more rapidly, and, on the other, completely new experimental approaches have become available. This situation resulted mainly from the introduction of programmable pulse transmitters and the separation of the experiment into preparation, evolution, and detection. In particular, the concept of two-dimensional spectroscopy has opened up new possibilities important for the analysis of complicated spectra and is able to provide information previously not accessible. As elsewhere, optimum application of the techniques and correct interpretation of the results require sound understanding of the underlying physical principles. Since a rigorous mathematical treatment is complicated and does not necessarily improve the comprehensibility, this article attempts to give an illustrative presentation of the new pulse techniques within the framework of the Bloch vector model. After a short introduction covering the basic principles, one-dimensional pulse techniques that can be applied using standard experimental equipment are dealt with. The main areas of application are signal assignment, sensitivity enhancement for measurements on less abundant nuclei, and selective excitation of individual resonances. Subsequently, the various techniques of two-dimensional NMR spectroscopy are treated: these enable shift correlations for different types of nuclei to be made, the presentation of spin multiplets without overlap, and the analysis of geometrical relations as well as of chemical exchange phenomena.

Modern Pulse Methods in High‐Resolution NMR Spectroscopy

Homonuclear two-dimensional 1H NMR of proteins. Experimental procedures

1H NMR spectroscopy of urine combined with pattern recognition (PR) methods of data analysis has been used to investigate the time-related biochemical changes induced in Sprague-Dawley rats by three model hepatotoxins: alpha-naphthyl isothiocyanate (ANIT), d-(+)-galactosamine (GalN), and butylated hydroxytoluene (BHT). The development of hepatic lesions was monitored by conventional plasma analysis and liver histopathology. Urine was collected continuously postdosing up to 144 h and analyzed by 600-MHz 1H NMR spectroscopy. NMR spectra of the urine samples showed a number of time-dependent perturbations of endogenous metabolite levels that were characteristic for each hepatotoxin. Biochemical changes common to all three hepatotoxins included a reduction in the urinary excretion of citrate and 2-oxoglutarate and an increased excretion of taurine and creatine. Increased urinary excretion of betaine, urocanic acid, tyrosine, threonine, and glutamate was characteristic of GalN toxicity. Both GalN and ANIT caused increased urinary excretion of bile acids, while glycosuria was evident in BHT- and ANIT-treated rats. Data reduction of the NMR spectra into 256 integrated regions was used to further analyze the data. Mean values of each integrated region were analyzed by principal components analysis (PCA). Each toxin gave a unique time-related metabolic trajectory that could be visualized in two-dimensional PCA maps and in which the maximum distance from the control point corresponded to the time of greatest cellular injury (confirmed by conventional toxicological tests). Thereafter, the metabolic trajectories changed direction and moved back toward the control region of the PR map during the postdose recovery phase. The combination of urinary metabolites which were significantly altered at various time points allowed for differentiation between biliary and parenchymal injury. This NMR-PR approach to the noninvasive detection of liver lesions will be of value in furthering the understanding of hepatotoxic mechanisms and assisting in the discovery of novel biomarkers of hepatotoxicity.

Nuclear Magnetic Resonance Spectroscopic and Principal Components Analysis Investigations into Biochemical Effects of Three Model Hepatotoxins

Digitisation and data processing in Fourier transform NMR

Application of resolution enhancement to absolute value presentation of FT NMR spectra

Discrimination between broad and sharp NMR signals and dynamic range improvement through Gaussian shaping of an FID

90 MHz proton n.m.r. spectra have been measured on solutions of deoxyhaemoglobin (Hb) in D2O in the presence and absence of dithionite (DT) and D-2,3-diphosphoglycerate (DPG) ions.Application of deconvolution and interpolative baseline correction software has enabled the pH dependence of the histidine C2 proton chemical shifts to be observed without the necessity of using high fields or elaborate pulse sequences. The n.m.r. data are interpreted in terms of a strong fast exchange interaction with DPG and a much weaker one, at the same site, for DT.Histidines β2 and β143 at the DPG binding site have been assigned to peaks in the proton n.m.r. spectrum. From the chemical shift behaviour of a selected resonance at different DPG concentrations, it has been shown that DPG and Hb bind with a 1:1 stoichiometry. The measured affinity constant is (5.1 ± 0.4)× 104 mol–1 and is independent of the ionised species of DPG present in the pH range 7.1–7.3.

High resolution proton nuclear magnetic resonance studies of interaction between deoxyhaemoglobin and small molecules. Dithionite and diphosphoglycerate

Automatic Recognition of Multiplet Patterns and Measurement of Coupling Constants in NMR and EPR Spectra through the Application of Maximum-Entropy Deconvolution

Anthony G. Ferrige

Papers

Digitisation and data processing in Fourier transform NMR

Application of resolution enhancement to absolute value presentation of FT NMR spectra

Discrimination between broad and sharp NMR signals and dynamic range improvement through Gaussian shaping of an FID

High resolution proton nuclear magnetic resonance studies of interaction between deoxyhaemoglobin and small molecules. Dithionite and diphosphoglycerate

Automatic Recognition of Multiplet Patterns and Measurement of Coupling Constants in NMR and EPR Spectra through the Application of Maximum-Entropy Deconvolution