[Interrelationship between two kinetic forms of pyruvate kinase in chicken liver during ontogenesis].

The value of the r coefficient for pyruvate kinase (rate at 1.5 mM of phosphoenolpyruvate per rate at 0.4 mM of phosphoenolpyruvate), i.e. ratio between the enzyme forms possessing the Michaelis-Menten and cooperative kinetics, in chicken liver during ontogenesis was found to be different. The embryonic liver contains predominantly the form with the cooperative kinetics, while in the livers of 1- and 10-day-old chickens the content of the other form is increased. In the livers of adult chicken the correlation between the two forms is that typical for 10-day-old chicken.