scholarly journals ESR and Optical Studies on the Interaction between Cu(II) and Pepsin

1978 ◽  
Vol 33 (5-6) ◽  
pp. 321-325 ◽  
Author(s):  
L. Sportelli ◽  
H. Neubacher ◽  
W. Lohmann
Keyword(s):  
Aqueous Solution ◽  
Electron Spin Resonance ◽  
Reaction Time ◽  
Conformational Change ◽  
Optical Spectroscopy ◽  
Electron Spin ◽  
Molar Ratio ◽  
Optical Studies ◽  
Spin Resonance

Abstract The interaction of Cu (II) with the protein pepsin has been investigated by means of electron spin resonance (ESR) and optical spectroscopy. Depending on the molar ratio of Cu(II) and pepsin in aqueous solution two different complexes are formed. A third complex can be detected after a reaction time of several days, attributed to a complex with a conformationally changed pepsin. The presence of inhibitors 1,2-epoxy-3-phenoxypropane (EPP) or diazoacetyl-ethylester (DAE) seems to hinder the conformational change. The structure of the three complexes is discussed.

ESR and Optical Studies on the Interaction between cis-Dichlorodiammine Platinum(II) and Tryptophan

1979 ◽  
Vol 34 (7) ◽  
pp. 1015-1018 ◽  
Author(s):  
Harald Neubacher ◽  
Peter Zaplatynski ◽  
Axel Haase ◽  
Wolfgang Lohmann
Keyword(s):  
Aqueous Solution ◽  
Electron Spin Resonance ◽  
Reaction Time ◽  
Esr Spectra ◽  
Electron Spin Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Optical Studies ◽  
Spin Resonance ◽  
Paramagnetic Complexes ◽  
Anticancer Compound

Abstract cts-Dichlorodiammine platinum(II), which is known to be an active anticancer compound, and tryptophan form paramagnetic complexes in aqueous solution. These can be detected by means of electron spin resonance spectroscopy (ESR) after a reaction time of several hours. The ESR spectra are interpreted to be due to Pt(III) in a low spin d7 configuration. The optical results obtained are in accordance with the assumption of columnar structures of the paramagnetic complexes

scholarly journals Antioxidant activity of Induna apple pomace extract

2005 ◽  
pp. 239-246 ◽  
Author(s):  
Sladjana Savatovic ◽  
Sonja Djilas ◽  
Vesna Tumbas ◽  
Jasna Canadanovic-Brunet ◽  
Gordana Cetkovic
Keyword(s):  
Aqueous Solution ◽  
Antioxidant Activity ◽  
Acetic Acid ◽  
Electron Spin Resonance ◽  
Hydroxyl Radicals ◽  
Electron Spin ◽  
Esr Spectroscopy ◽  
Methanol Extract ◽  
Apple Pomace ◽  
Spin Resonance

Different concentrations ofmethanol aqueous solution with or without 0.5% acetic acid and 80% acetone were used to achieve the highest yield of extraction of phenolics from Induna apple pomace. The highest content of phenolics (6.38 mg/g) was detected in the 80% methanol extract. The influence of 80% methanol extract of Induna apple pomace on stable l,l-diphenyl-2-picrylhydrazyl (DPPH) and reactive hydroxyl radicals has been investigated by electron spin resonance (ESR) spectroscopy. Based on the obtained results it can be concluded that the investigated extract is more effective in the DPPH test than on the DMPO-OH scavenging. In both cases antioxidant activity increased with increasing concentration of the investigated extract. The high contents ofphenolics (6.38 mg/g), flavonoids (1.01 mg/g) and flavan-3-ols (0.70 mg/g) in 80% methanol extract indicated that these compounds contributed to the antioxidant activity of Induna apple pomace.

Synthesis and electron spin resonance studies of a Co(II) complex with a tetradentate macrocyclic Schiff base ligand

1977 ◽  
Vol 55 (1) ◽  
pp. 70-75 ◽  
Author(s):  
Amikam Reuveni ◽  
Vincenzo Malatesta ◽  
Bruce R. McGarvey
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Ground State ◽  
Molar Ratio ◽  
Lewis Bases ◽  
Spin Resonance ◽  
Frozen Solutions ◽  
Hamiltonian Parameters ◽  
Simulation Of Spectra ◽  
Macrocyclic Schiff Base

The synthesis, physical properties, and electron spin resonance of frozen solutions of CoTAAB(NO3)2 (TAAB = tetrabenzo[b,f,j,n] [1,5,9,13]tetraazacyclohexadecine) are reported. The spin Hamiltonian parameters were elucidated by simulation of spectra assuming axial g and 59Co hyperfine tensors and including nuclear quadrupole and Zeeman contributions. Electron spin resonance spectra in solvents such as methanol, acetone, and dimethylformamide are typical for a low spin complex (S = 1/2) and are nearly identical with [Formula: see text] and [Formula: see text]. In pyridine and quinoline a complex with a molar ratio solvent/ligand of 1:1 is formed with the solvent which gives [Formula: see text]and [Formula: see text] much closer to [Formula: see text]. In strong Lewis bases, such as piperidine, a 2:1 complex is formed and no esr signal is found. Evidence is presented to show that these 2:1 complexes with strong Lewis bases are S = 1/2 complexes with a low lying S = 3/2 state that is partially populated at room temperatures. This behaviour is accounted for in terms of a theory derived for a 2A1 ground state with a low lying quartet state which could become the ground state in strong basic solvents.

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