ABSTRACT
We have investigated the effect of theophylline on the kinetics of the catalytic subunit of protein kinase and related factors in lung tissue. The results show that the point of highest concentration of the C subunit of protein kinase which is active in casein phosphorylation is at 3h of incubation time, but in the presence of 100 micro g/ mL and 10micro g/mL the ophylline, this is shifted to 1.5 and 2.5 hrs, respectively. Also the maximum concentration of cAMP for the control is at 2.5 h of incubation time, but in the treated samples shifts to 2.15 and 1.15 hrs, respectively. Inhibitor protein content also changes considerably in the presence of 10micro g/mL theophylline. The results suggest an effect of theophylline on the function of cAMP-dependent protein kinase