Glycolysis in permeabilized L-929 cells

Abstract

Mouse L-929 cells permeabilized with dextran sulphate (DSP cells) carry out glycolysis when supplemented with glucose, ATP and NAD+ in a suitable incubation buffer. Glycolytic rates were linear and generally independent of cell density over the range examined (1 x 10(6)-10 x 10(6) cells/ml). Electron microscopy revealed characteristic changes in DSP cell ultrastructure, notably for nuclei and mitochondria. Some cells lacked plasma membranes, while others appeared intact. In the latter case, estimates of the lesion size in plasma membranes were obtained from volume of distribution studies using 14C-labelled proteins, and infiltration of fluorescein isothiocyanate dextran. The results indicated the presence of lesions large enough to allow globular proteins of about 400 kDa to cross the cell surface. In spite of that, only about 10% of total cell protein exited from DSP cells during a 30 min incubation period. We propose that none of the glycolytic enzymes in DSP cells can exist completely in solution in the 'cytosol', suggesting extensive enzyme organization. The results are interpreted within the broader picture of metabolic organization in animal cells and the nature of the 'cytosol'.