Increased cyclic nucleotide phosphodiesterase activity in a mutant S49 lymphoma cell. Characterization and comparison with wild type enzyme activity.

Abstract

We have characterized the markedly elevated cyclic AMP and cyclic GMP phosphodiesterase activities of a recently isolated S49 mouse lymphoma mutant, termed K30a, and compared both activities to enzyme activities in the parental wild type S49 cell.cAMP phosphodiesterase activity in K30a appears to be slightly larger than the major wild type CAMP-hydrolyzing enzyme, in sucrose gradient sedimentation and gel filtration.Both cAMP phosphodiesterase activities elute from DEAEcellulose columns at a 0.4 M salt concentration.cAMP phosphodiesterase in K30a, as compared to wild type cells, exhibits a component of activity with higher affinity for substrate (K,,, = 0.15 f 0.02 versus 0.53 2 0.05