Multinuclear and Multidimensional Nmr Methodology for Studying Individual Water-Molecules Bound to Peptides and Proteins in Solution - Principles and Applications

Progress in Nuclear Magnetic Resonance Spectroscop

The O-17-NMR shielding range and shielding time scale and detection of discrete hydrogen-bonded conformational states in peptides

The O-17-NMR shielding range and shielding time scale due to hydrogen-bonding interactions in peptides are critically evaluated relative to those of H-1-NMR. Furthermore, the assumptions and conclusions in previous O-17-NMR studies on the detection of discrete conformational states in peptides (V. Tsikaris et al., Biopolymers, 2000, Vol. 53, pp. 135-139) are reconsidered. Consistent examination of the method demonstrates that although O-17 shieldings of peptide oxygens are very sensitive to hydrogen bonding interactions, the O-17-NMR shielding time scale is not advantageous compared to that of H-1-NMR, and thus it is not suitable for the detection of discrete hydrogen-bonded conformational states in peptides. O-17-NMR spectroscopy is prone to interpretation errors due to the formation of O-17-labeled impurities during the synthetic procedures (A. Steinschneider et al., International Journal of Peptide and Protein Research, 1981, Vol. 18 pp. 324-333). (C) 2001 John Wiley & Sons, Inc.Biopolymer

O-17 Nmr-Studies of Hemoproteins and Synthetic Model Compounds in the Solution and Solid States

Progress in Nuclear Magnetic Resonance Spectroscop

O-17 Nmr-Spectroscopy as a Tool for Studying Synthetic Oxygen Carriers Related to Biological-Systems - Application to a Synthetic Single-Face Hindered Iron Porphyrin Dioxygen Complex in Solution

J Am Chem So

Phenolic compounds and antioxidant activity of olive leaf extracts

The total phenolic content and antioxidant activities of olive leaf extracts were determined. Plant material was extracted with methanol and fractionated with solvents of increasing polarity, giving certain extracts. The qualitative changes in the composition of the extracts were determined after the storage of leaves for 22 h at 37 degrees C, before the extraction. Total polyphenol contents in extracts were determined by the Folin-Ciocalteu procedure. They were also analysed by liquid chromatography-mass spectrometry. Their antioxidant activities were evaluated using the diphenyl picrylhydrazyl method and the beta-carotene linoleate model assay. Moreover, the effects of different crude olive leaf extracts on the oxidative stability of sunflower oil at 40 degrees C and sunflower oil-in-water emulsions (10% o/w) at 37 degrees C, at a final concentration of crude extract 200 mg kg(-1) oil, were tested and compared with butylated hydroxyl toluene.Nat Prod Re