Kinetic properties of beta-galactosidase in Morquio B disease.

Some kinetic Properties of beta-galactosidase in crude extracts of cultured fibroblasts obtained from patients with Morquio B disease, GM1-gangliosidosis and from the controls were compared. The main defect in Morquio B seems to be the lowering of enzyme affinity to the substrates, while in the case of GM1-gangliosidosis of infantile type 1 a dramatic decrease of Vmax value concomitant with normal KM value was observed. Based on these observations possible interpretations of the clinical picture are discussed.