Characterization of native 40S particles from Krebs II mouse ascites tumor cells. I. Phosphorylation in vitro of non ribosomal proteins by a cAMP independent protein kinase

Abstract

In the presence of [ γ 32-P] ATP or [ γ 32-P] GTP 4 non ribosomal proteins (M r 110,000; 105,000; 89,000 and 25,000) of the native 40S subunit became phosphorylated. The protein kinase responsible for this phosphorylation could be removed by treatment with 0.5 M KCl. Sucrose density gradient analysis showed that the endogenous enzyme activity sedimented with approx. 7.5S.