PROTEIN KINASE ACTIVITY ASSOCIATED WITH THE SURFACE OF GUINEA PIG MACROPHAGES

Macrophages play multiple roles in host defense, e.g. in the induction of the immune response (1), in phagocytosis (2), and in killing bacteria and tumor cells (3). In many of its biological functions the role of the surface membrane is prominent. Macrophages can undergo extensive alterations in morphology and functions; particularly noteworthy is the increase of defense properties associated with bacterial infections (4). For a variety of enzymes, functional alterations have been shown to be based on phosphorylation reactions (5). This paper documents the identification of a protein kinase associated with the outer surface of guinea pig peritoneal macrophages. The surface-associated protein kinase is shown to transfer ,/-phosphate of ATP to certain endogenous macrophage proteins and also to added acceptor protein.