Preferential Phosphorylation of NP‐Protein of Influenza A2 Virus by Virion‐Associated Protein Kinase

Abstract

Influenza A2 virions contain protein kinase activity which was stimulated, as are other virion-associated kinases, with Mg++ and Nonidet-P 40, but not with cyclic AMP. The kinase phosphorylated only the NP-protein fraction of the influenza virions in the in vitro reaction. No influenza virion proteins were phosphorylated significantly during virus production in infected [chick] chorioallantoic membranes. The in vitro and in vivo phosphorylations of influenza viral proteins were compared with those of Sendai virus.