The effect of ultrasonic vibrations on the protein-synthesizing activity of microsome preparations from rat liver

Publisher Website
Google Scholar
Abstract
The effect of ultrasonic vibrations on microsomes from normal and regenerating liver and on ribonucleoprotein particles prepared from microsomes by treatment with detergents and KCl was investigated. The amino acid-incorporating activity was diminished after treatment with ultrasonic vibrations both in the presence and in the absence of reducing agents. The enzymes present in the soluble fraction of the cell and necessary for protein synthesis were not affected. Protein and ribonucleic acid were released from the various preparations after treatment with ultrasonic vibrations. Polyuridylic acid restored the ability of ultrasonically treated ribonucleoprotein particles to incorporate phenylalanine into protein. The activity of ultrasonically treated microsomes could not be restored by polyuridylic acid. The application of ultrasonic vibrations on microsomes caused a several-fold increase in phosphodiesterase activity as measured by the breakdown of [H3]polyuridylic acid. As a breakdown product, an increased amount of 5[image]-uridine monophosphate (5[image] -UMP) was obtained. There was no significant effect on the breakdown by ultrasonically treated ribonucleoprotein particles. Electron microscopy showed that on treatment by ultrasonic vibrations the microsomal fraction retained membranes and particles. No apparent change in the structure of isolated ribonucleoprotein particles was observed. The membrane-bound enzyme glucose 6-phosphatase was not destroyed by treatment with ultrasonic vibrations for 1 minute.