Cyclic AMP-dependent protein kinase content of murine T and B lymphocytes

Murine splenic lymphocytes have been separated by non-activating procedures into enriched T and B cell populations. Cyclic AMP-dependent protein kinase (cAPK) activity has been measured in those separated cell types by histone phosphorylation. As in other tissues, lymphocyte cAPK activity was found to be predominantly a soluble enzyme. By an analysis of cyclic AMP (cAMP) activation of enzyme activity it was shown that: (1) the basal activities were indistinguishable between these major lymphocyte subpopulations, (2) the Ka values for cAMP activation were identical for the two cell types (24 nM cAMP), and (3) the Vmax for enzyme activity was higher in T (5.47 pmole/min/10(6) cells) than in B (3.58 pmole/min/10(6) cells) cells. DEAE-cellulose chromatography experiments with mixed and enriched splenic lymphocyte populations extended and amplified this quantitative difference between T and B cells.