The identification and characterization of a cyclic AMP dependent protein kinase on rabbit reticulocyte ribosomes

Abstract

A cAMP dependent protein kinase which appears to be intimately associated with rabbit reticulocyte ribosomes has been partially purified and characterized. The enzyme readily phosphorylates salt-washed reticulocyte ribosomes and this activity is stimulated by cAMP. Although the enzyme appears to possess broad specificity and phosphorylates various substrates, it demonstrates its greatest dependency for cAMP when ribosomes are utilized as substrate. A comparison of the DEAE-cellulose chromatography of the enzyme with the elution patterns of protein synthesis initiation factors shows the kinase to be distinct from any of these factors.