Differences in purine metabolizing enzyme activities in human leukemia T-cell, B-cell and null cell lines.

Clear metabolic differences between T- and B-cells were demonstrated. Both adenosine deaminase (ADA) and nucleoside phosphorylase (NP) activities increased during logarithmic growth and then decreased in T-cells, but remained essentially constant during the growth cycle of B-cells. When these enzyme activities were examined in a number of T-cell, B-cell, and null cell lines, ADA activity was clearly higher in T-cells as compared to all others. With NP, the opposite appeared to be true, although the differences were much smaller and not statistically significant in all instances. No clear differences were found in the isoenzyme distributions of both enzymes in the various cell types.