Soluble and membrane-bound protein kinases in newborn and mature rat brain

We studied the developmental changes of soluble and membrane-bound protein kinases (EC 2.7.1.37) in rat brain and found that the elution profiles from a DEAE-cellulose column by NaCl of adenosine-3':5'-monophosphate (cyclic AMP) dependent protein kinase from cytosol were not significantly different in newborn (0.19 M NaCl) vs. mature (0.21 M NaCl). In addition, there was little change in Kd for cyclic AMP binding of newborn and mature soluble enzyme. In contrast, using endogenous protein as the phosphate acceptor, cyclic AMP dependent and calcium-dependent protein kinases from brain synaptic membranes of mature rats were significantly higher than that of newborn rats.