Membrane Marker Enzyme Activities Research Articles

Cellular membranes: Membrane marker enzyme activities in synchronized mouse leukemic cells L 517SY

The activities of UDPase, a smooth endoplasmic reticulum marker enzyme; esterase, a rough endoplasmic reticulum marker enzyme, and 5′-nucleotidase, a plasma membrane marker enzyme were measured as a function of cell cycle time in L 5178Y cells synchronized with excess thymidine and colcemid. UDPase was active mainly in the S period of the cell cycle with a peak 6.5 h post mitosis. 5′-Nucleotidase was active mainly in the S period of the cell cycle with a peak 5.0 h post mitosis. Esterase was active throughout the cell cycle but mainly in early S period. Each enzyme followed a peak pattern.