A Ribosome Dissociation Factor from Rabbit Reticulocytes

Abstract

A ribosome dissociation factor has been detected in an extract of ribosomal particles from rabbit reticulocytes. This factor dissociates free ribosomes from reticulocytes and also from Escherichia coli; it does not dissociate ribosomes complexed with peptidyl-tRNA and mRNA. The reaction appears to be stoichiometric rather than catalytic; it reaches completion in one minute at 37 degrees C, but is very slow at 0 degrees C, and it is antagonized and reversed by Mg(++). Reticulocyte dissociation factor thus closely resembles that from E. coli. However, the activity has been found primarily associated with the native large subunits rather than the small subunits in lysates.