[Initiation of kinetic and thermodynamic effects in cells]

Conditions of initiation of thermodynamic and kinetic isotope effects of carbon in metabolic processes were investigated. Major role of kinetic effects appearing in the branching sites of metabolic pathways was substantiated. The kinetic isotope effect in piruvate decarboxylation reaction was shown to be the principal element of the mechanism of isotope fractionation of carbon in the cell.