Characteristics of galactokinase and galactose-1-phosphate uridyltransferase in cultivated fibroblasts and amniotic fluid cells.

The kinetic characteristics of galactose-1-phosphate uridyltransferase and galactokinase in cultivated fibroblasts and amniotic fluid cells were investigated. The Km values of galactokinase for galactose at 2.0 mM ATP are 0.34 mM in amniotic fluid cells and 0.48 mM in fibroblasts. The Km values for ATP at 0.5 mM galactose are 1.25 mM and 2.10 mM. Transferase and galactokinase activities and protein content increase logarithmically during the growth of cultivated cells. The specific activity of both enzymes also increases and reaches a maximum level 10--15 days after subculture. The specific activity of transferase increases faster than that of galactokinase in the case of amniotic fluid cells. In the case of fibroblasts the specific activity of galactokinase increases faster than that of transferase.