CERTAIN DEHYDROGENASE ACTIVITIES AND DRY WEIGHT OF NORMAL AND MALIGNANT MAST CELLS

Abstract

Total dry weight of individual lyophilized peritoneal malignant mouse mast cells (line P-815, Dunn-Potter) was found to have a mean value of 219 ±7 pg compared with 2.4 times this for normal rat peritoneal mast cells. Lactic, glucose 6-phosphate, 6-phosphogluconate and isocitric dehydrogenase activities in suspensions of whole and of disrupted malignant cells were measured fluorometrically. The lactic dehydrogenase activity per unit weight of protein of the malignant cells was found to be about 19 times that of the normal cells, and the other enzymes, which do not appear to be present in the normal cells, were demonstrated in the malignant cells. Freeze-thawing, temperature and time of storage and presence of protein influenced the individual enzyme activities differently. Protein was generally protective against inactivation, and that due to freeze-thawing, which was used to disrupt cells for enzyme liberation, was minimized in the presence of serum or plasma albumin. Protein did not, however, protect against enzyme inactivation because of prolonged storage of the cells in the frozen state.