[Peptidomes of the brain, heart, lung, and spleen of a rat: similarity and differences].

Profiles of endogenous peptides of the brain, heart, lungs, and spleen of a rat have been obtained by chromatographic and mass spectrometric analysis of low-molecular-mass fractions of tissues extracts. The concentrations of the corresponding components have been estimated from the intensities of 119 major chromatographic peaks. The total content of peptides in tissues, nmol/g (mg/g), was 3-13 (0.005-0.05) for the brain, 7-27 (0.01-0.10) for the heart, 17-68 (0.02-0.25) for the lungs, and 80-300 (0.08-1.30) for the spleen. A comparative analysis of the data obtained for the organs has been performed. The primary structures for 68 peptides have been determined; most substances (>70%) have been identified as hemoglobin fragments. It has been shown that many of the peptide components identified (>75%) are common for several organs. The relationship between the composition, the mechanism of formation, and the functional role of peptidomes of the organs, tissues, and cells of higher organisms has been discussed.

[Fragments of functional proteins in the primary culture of human erythrocytes].

According to previously reported data, the supernatant of a primary culture of human erythrocytes contains 33 hemoglobin fragments. An analysis of the supernatant of a 20% (v/v) suspension of human erythrocytes allowed us to identify additionally four peptides whose precursors are cytoplasmic beta-actin (two fragments), fructose diphosphate aldolase B, and an unknown protein, as well as the amino acids tyrosine and tryptophan. The composition and the content of the components of the supernatant did not depend on the age or blood group of donors. The dynamics of accumulation in the supernatant (20-80 min of incubation) of the 14 hemoglobin fragments with the most reliably reproducible contents was obtained. The content of six peptides increased more than twofold between 20 and 40 min of incubation: the maximum increase in concentration was observed between 40 and 80 min (140%). The level of peptides that had the maximum concentration at the end of incubation was about 1000 pmol/ml of sedimented erythrocytes. The biological effects of the peptides identified in the supernatant of erythrocytes involve the stimulation of proliferation and hemopoiesis, suppression of proliferation, a bactericide effect, etc. These effects indicate the physiological importance of peptide release by erythrocytes. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru.

[Isolation and structure of peptides from oat (Avena sativa) seedlings].

The level of proteolytic activity in tissues of oat seedlings was characterized under acidic conditions, and the number and content of the main components in low-molecular-mass fractions of the extract were determined. The structures of the majority of predominant peptide components isolated from the extract were studied. The use of a database of protein structures helped suggest possible structures of protein precursors of the peptides isolated. Detailed information on a plant peptidome was obtained for the first time.

[Proteolytic degradation of hemoglobin in erythrocytes results in formation of biologically active peptides]. / Proteoliticheskaia degradatsiia gemoglobina v éritrotsitakh privodit k obrazovaniiu biologicheski aktivnikh peptidov.

The formation of biologically active hemoglobin fragments in human erythrocytes was studied. The structures of 33 peptide products of intraerythrocytic hemoglobin cleavage were determined. Based on an analysis of these sequences, a model of the stepwise degradation of the hemoglobin alpha- and beta-chains was suggested. The processes of peptide formation in a cell-free erythrocyte lysate system were studied. The involvement of an enzymatic complex of the cell membrane fraction was demonstrated. It was found that the cells of a surviving human erythrocyte culture secrete short (of 5-20 amino acid residues) peptides, and the structures of 36 peptides were determined. The dynamics of peptide secretion was investigated, and preliminary data on the energy-dependence of this process were obtained. Based on the experimental results, a model describing erythrocytes as an endocrine gland was suggested.