Superoxide scavenging by thiol/copper complex of captopril--an EPR spectroscopy study.

Scavenging of superoxide radical by angiotensin converting enzyme (ACE) inhibitor captopril (CAP), a thiol compound, was studied by several investigators and the results were contradictory; while some reported a high superoxide scavenging activity of CAP others found that CAP removed superoxide inefficiently. In this work we show that in the presence of copper ions the apparent rate of superoxide removal by CAP (molar ratio CAP:CuSO4 4:1) was two orders of magnitude higher (approximately 1.5 x 10(5) M-1s-1 at pH 7.

[EPR spin trapping of reactive oxygen products of the respiratory burst of phagocytes (use of EPR spectroscopy in biology and medicine. II)].

Respiratory burst during phagocytosis of human neutrophils is connected with the production of superoxide anion radical O2.-. This radical changes into further bioreactive oxygen products (especially H2O2 and .

Comparison of perturbation effect of propranolol, verapamil, chlorpromazine and carbisocaine on lecithin liposomes and brain total lipid liposomes. An EPR spectroscopy study.

Effect of verapamil, propranolol, chlorpromazine and carbisocaine on dynamics and/or order of liposomes (perturbation effect), prepared from different molar ratios of lecithin (PC) and rat brain total lipids (TL) was studied by EPR spectroscopy using spin probes 16-doxyl stearic acid and 14-doxyl phosphatidylcholine. The PC liposomes had higher dynamics and/or lower order than the TL liposomes. The perturbation effect of the drugs depended largely on the lipid composition of the liposomes.

[Use of electron paramagnetic resonance spectroscopy spin labels in studying the properties of biological membranes].

Electron paramagnetic resonance (EPR) spectroscopy of spin labels has become a widely spread method in biochemistry, molecular biology, and medicine. After a brief view on the structure and functions of biological membranes, basic principles of EPR and particularly of the spin labeling technique are presented. Applications of this technique are demonstrated on the study of various properties of biological membranes, such as phase transition of lipids, properties of different membrane parts, permeability of membranes, inner volumes of liposomes and cells, membrane potentials, lateral diffusion, lipid-protein interaction, and determination of oxygen concentration.