[Change in aldolase activity in the organs of mice in the process of hepatoma 22a development].

The aldolase activity was measured using two substrates fructose-I-phosphate (FIP) and fructose-1,6-diphosphate (FDP) in the supernatant fraction of homogenates of different mice organs (liver, muscle, brain) and hepatoma tissues during growth of hepatoma 22a. Kinetic parameters Km and Vmax were calsulated. The most essential changes in the activity of aldolase were found during the latent and terminal stares of the hepatoma development. The changes in the aldolase activity observed during development of hepatoma 22a were characterized by altered substrate specificity VFDP /VFIP activity gatio). This ratio was not changed distinctly in liver tissue; in muscles the value decreased from 50 (tumor-free control) to 15 during terminal stages; in brain, to the contrary, it was increased from 20 to 50. The values of Km, Vmax and VFDP /VFIP were similar both in the hepatoma at the eleventh day and in normal brain tissue. The specific inhibition of FDP aldolase activity by ATP was found. Substitution of aldolase B by aldolase AC apparantly ossurred in hepatoma 22a. The data obtained suggest that alteration in the parameters studied may be due to variation in the ration of isozymes.