On the variation in enzyme activities during the growth of burkitts lymphoma cells in suspension culture

Abstract

1. 1. The growth characteristics of Burkitt's lymphoma cells in suspension culture have been studied, and a mean population doubling time of 20–21 hr established for this cell line under a range of nutritional and physical conditions; data which have provided a basis for the assessment of the reproducibility of the culture techniques and conditions which were employed in the subsequent studies. 2. 2. Activities of lactate dehydrogenase (LDH), aldolase and esterase, as well as the cellular content of total soluble protein, and the isoenzyme pattern of LDH, were monitored in randomly growing Raji cells for the duration of a complete growth cycle. 3. 3. In this period, the temporal pattern of variation in the levels of total soluble protein were seen to reflect alterations in LDH activity during a single growth cycle. 4. 4. The fluctuations observed in LDH activity were greater than those observed for either aldolase or esterase activity, and, from the data considered, the maximum degree of variation appeared to be confined to the initial stages of growth. 5. 5. Extracellular levels of LDH activity remained relatively constant throughout the growth cycle. so that the large fluctuations in intracellular LDH activity could not be attributed to either secretion or leakage of the enzyme into the culture medium. 6. 6. No gross changes in the pattern of LDH isoenzymes in these Raji cells were detected during the course of a single growth cycle.