Fröhlich theory of coherent excitations in biological systems is analyzed. L-lactate dehydrogenase kinetics is studied using the activation process model for non-equilibrium cases. The model explains the process of energy accumulation necessary for carrying out catalytic reactions in a living cell by means of interaction of quantum subsystems with thermal equilibrium radiation, light, and radiation energy of metabolic processes occurring in the cell. It is shown that lactate dehydrogenase catalyzes the interconversion of pyruvate and lactate with concomitant interconversion of NADH and NAD+ in three ways, that is, three reactions occur simultaneously. Negative information entropy for the reactions under consideration is calculated. Its absolute value is equal to that of information entropy of the elementary activation act. This fact ensures the principle of stable non-equilibrium and indicates the reaction under consideration belongs to a living cell.