[Study of oxygen accumulation in pea chloroplasts with spin labels].

Oxygen evolution in chloroplasts was studied by nitroxide fatty probes, introduced into chloroplasts membranes. The values of K(e)[O²] were determined from the measuring kinetics of nitroxide reduction under permanent illumination at two values of the microwave field, where K(e) was the constant of spin exchange between nitroxide and oxygen, [O²] --oxygen concentration. It was shown that in chloroplasts membranes, in contrast to liposomes there was no oxygen in the dark.

[Study of lysozyme by a spin-label method in the 2-mm range].

Two millimeter range ESR-spectroscopy was used to measure the values of magnetic resonance parameters of egg lysozyme samples modified with nitroxyl label 4-(iodine-acetamide)-2,2,6,6-tetramethylpiperidine-1-oxyl by hist-15 residue. It has been shown that in a lyophilic sample the spin label forms a hydrogen bond with the protein group and when the sample is moistened--with water molecules. Temperature changes of the pattern of ESR line are analysed.

[Study of molecular mobility in biological membranes by 2-mm band ESR spectroscopy].

Temperature relationship was measured of ESR spectra of spin probes--derivatives of fatty acids whose nitroxyl fragments are incorporated into surface and inner layers of phosphatidylcholine liposomes (T = 180-260 K), as well as of the probe in model ethanol solution (T = 110-220 K). Data on the nature and rotation frequency of probe nitroxyl fragments were obtained from the analysis of the spectra. It was shown that the frequency of the probes movement in the systems under study corresponds to the slow movement region, i.