Cross-Relaxation Effects in Pulsed-Field-Gradient Stimulated-Echo Measurements on Water in a Macromolecular Matrix

Peschier, L.J.C.; Bouwstra, J.A.; Bleyser, J. de; Junginger, Hans E.; Leyte, J. C.

doi:10.1006/jmrb.1996.0024

Cited by 49 publications

(80 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the hydrolysis of the peptide to produce free TFA undoubtedly contributes to this discrepancy, chemical exchange effects may also be a factor complicating these analyses, especially when the LED pulse sequence is used. 25,26,28 Interaction of elastase with TFA-Glu-Ala-NHPh-p-CF 3 using 19 …”

Section: Resultsmentioning

confidence: 99%

¹⁹F diffusion NMR analysis of enzyme–inhibitor binding

Derrick

Lucas

Dimicoli

et al. 2002

Magnetic Reson in Chemistry

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

¹⁹F diffusion NMR analysis of enzyme–inhibitor binding

Derrick

Lucas

Dimicoli

et al. 2002

Magnetic Reson in Chemistry

View full text Add to dashboard Cite

show abstract

“…All the steroid compounds (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) were measured at the following conditions.…”

Section: Methodsmentioning

confidence: 99%

“…[3][4][5][6][7][8] Although, many reports can be found about correlation between molecular weight and diffusion coefficient of small molecule in polymer or polymer gel, [9][10][11] systematic studies of diffusion coefficient of small molecule itself in solution have not been reported so far.…”

mentioning

confidence: 99%

Intermolecular Hydrogen Bonding of Steroid Compounds: PFG NMR Diffusion Study, Cold-Spray Ionization (CSI)-MS and X-Ray Analysis

Shikii

Seki

Sakamoto

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

NMR is one of the most effective analytical instrumentations to elucidate the dynamic nature of organic molecule in solution. 1,2) Other instrumental analyses such as MS and Xray help to reveal the role of hydrogen bonding in solution which are of great importance in the field of biology and organic chemistry.A great number of reports with respect to development of the new NMR-based techniques using nuclear Overhauser effect (NOE) and molecular diffusion measurement have been presented. [3][4][5][6][7][8] Although, many reports can be found about correlation between molecular weight and diffusion coefficient of small molecule in polymer or polymer gel, [9][10][11] systematic studies of diffusion coefficient of small molecule itself in solution have not been reported so far.Recently, we reported the structure analysis, in solution, of five steroid compounds (progesterone 1, estrone 2, cortisone 3, hydrocortisone 4, cholic acid 5) by the use of cold-spray ionization (CSI)-MS, 12) PFG NMR and X-ray analysis. 13)Narcissistic aggregation (formation of large-scale aggregated chain structure or cluster) based on the intermolecular hydrogen bonding at the hydroxyl and carboxyl functionalities was confirmed. Moreover, in this previous report, reasonable correlation between hydrogen bonding and cluster formation was obtained in the crystal as well as in solution. However, quantitative analysis based on strength of the hydrogen bonding and diffusion coefficient was not achieved by PFG NMR. Therefore, accurate NMR diffusion experiments on the five initial steroids as well as seven additional one are presented. The formation of the hydrogen bound clusters in diluted solution quantified by diffusion coefficient measurements. The results obtained from PFG NMR are further confirmed and compared with the results obtained by CSI-MS and X-ray analysis. Results and DiscussionsA total of twelve steroid compounds including the previous steroids (1-5, 13) androsterone 6, norethisterone 7, dehydroepiandrosterone acetate 8, 11a-hyrodoxyprogesterone 9, corticosterone 10, prednisolone acetate 11, cholic acid methyl ester 12), have been analyzed. CSI-MS measurements are performed to analyze the nature of the steroids in solution. As previously described, the twelve compounds are classified through three hydrogen bonding types, strong (type A), weak (type B) and none (type C). The strength depends on the number of hydroxyl group(s) in the backbone chain. Compounds 6-12 exhibit significant correlation between the number of hydrogen bonding and the cluster formation as observed in the CSI-MS spectra. Typical pattern of the CSI-MS spectra of each type, A (11), B (9) and C (8) are shown in Fig. 1. Na ϩ attached to the molecular ion peaks are undeniably observed in type A compounds, which includes 3, 4, 5, and 11. Rather weak aggregation is observed in type B spectra, compounds 2, 6, 7, 9, 10, and 12 whereas no chain interaction is seen for compounds 1 and 8 (type C). The CSI-MS classification of the cluster type is summarized in Chiba, Japan:...

show abstract

“…Investigations of self-diffusion of water in a macromolecular matrix showed that the amplitude of the stimulated echo could be influenced by chemical exchange and magnetization exchange (or cross-relaxation) between free water protons and water molecules bound to polymer or biopolymer (15,16). There are different mechanisms which lead to changes of the true diffusion coefficient D of water when it is measured by the PFGSE method and the classical expression for the stimulated echo amplitude is applied (14).…”

Section: Theorymentioning

confidence: 99%

Self-diffusion anisotropy of water in sheep Achilles tendon

et al. 2005

View full text Add to dashboard Cite

The principal values of the diffusion tensor of free water in the pores of sheep Achilles tendon were determined. For this purpose, the azimuthally angular dependence of the self-diffusion coefficient was measured using a radiofrequency tilt coil and pulsed-field-gradient stimulated-echo (PFGSE) NMR. Combining the PFGSE with multiple acquisitions of Hahn echoes using the Carr-Purcell-Meiboom-Gill pulse sequence reduced the measuring time. The diffusion measurements revealed two diffusion process characterized by a fast and a slow effective diffusion coefficient. A model which describes the stimulated-echo amplitude, encoded by the water diffusion and magnetization transfer, was used for evaluation of the fast diffusion coefficients. The fast diffusion process characterizes the water molecules in pores surrounding the collagen fibrils. The diffusion coefficients characterizing the fast process show a well-defined anisotropy. The principal values of the diffusion tensors were determined assuming the elongated pores to be oriented parallel to the tendon fibrils and thus the orientation distribution function of the pores followed that of the collagen fibrils. The average aspect ratio of pores was estimated from the principal values of the water diffusion tensor and is suitable to characterize quantitatively the changes in tendon morphology due to healing or aging. The methods in this investigation can also be applied to measurements of the diffusion anisotropy using ex situ NMR sensors.

show abstract

Cross-Relaxation Effects in Pulsed-Field-Gradient Stimulated-Echo Measurements on Water in a Macromolecular Matrix

Cited by 49 publications

References 2 publications

¹⁹F diffusion NMR analysis of enzyme–inhibitor binding

¹⁹F diffusion NMR analysis of enzyme–inhibitor binding

Intermolecular Hydrogen Bonding of Steroid Compounds: PFG NMR Diffusion Study, Cold-Spray Ionization (CSI)-MS and X-Ray Analysis

Self-diffusion anisotropy of water in sheep Achilles tendon

Contact Info

Product

Resources

About

Cross-Relaxation Effects in Pulsed-Field-Gradient Stimulated-Echo Measurements on Water in a Macromolecular Matrix

Cited by 49 publications

References 2 publications

19F diffusion NMR analysis of enzyme–inhibitor binding

19F diffusion NMR analysis of enzyme–inhibitor binding

Intermolecular Hydrogen Bonding of Steroid Compounds: PFG NMR Diffusion Study, Cold-Spray Ionization (CSI)-MS and X-Ray Analysis

Self-diffusion anisotropy of water in sheep Achilles tendon

Contact Info

Product

Resources

About

¹⁹F diffusion NMR analysis of enzyme–inhibitor binding

¹⁹F diffusion NMR analysis of enzyme–inhibitor binding