EN
Protein kinases tightly associated with chick embryo brain ribosomes washed with Triton X-100 and KCl were characterized by their ability to phosphorylate ribosomes and two exogenous substrates, histone IIA and casein. c-AMP-dependent kinase (PKA) and casein kinases (CK1, CK2) were examined in the presence of specific modulators by SDS/ PAGE followed by renaturation in gel assay according to Kameshita & Fujisawa (Anal. Biochem. 1989, 183, 139-143). Basing on these data it can be presumed that PKA activity increases, but the levels of CK2 and CK1 decrease during chick embryo development.