[Intramolecular isotope distribution of metabolites in the glycolytic chain]

Based on the mechanism of the fractionation of carbon isotopes in the glycolytic chain proposed earlier, a method for the qualitative prediction of intramolecular isotope distribution of metabolites synthesized through the glycolytic chain and conjugated reactions was developed. Among them are fatty acids, monoterpenes, hopanoids, branched amino acids, amino acids of the family of trioses, metabolites synthesized by the shikimate pathway, metabolites of the Krebs cycle, amino acids of the family of ketoglutaric and oxalacetic acids. The method was tested by comparing the natural and theoretically predicted isotope distributions of carbon. The model for the description of theoretical isotope distributions is based on oscillations in the glycolytic chain. In the glycolysis phase, an isotope effect of decarboxylation of pyruvate arises, which determines the experimentally observed isotope inhomogeneity of metabolites. The isotope distributions of carbon depend on the sequence of syntheses of metabolites in the cell cycle, which corresponds to the degrees of exhaustion of the pyruvate depot that supplies structural units for the synthesis. In repeated cycles, the syntheses of metabolites occur in phase in addition to the carbon flux passing through the glycolytic chain, a carbon flux entering from the photorespiratory chain is involved in the synt, which is enriched in carbon heavy isotope. This flux is used, in particular, for the formation of carbon fragments of complex molecules.