QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Von Der Decken, A. Search for Related Content PubMed PubMed Citation Articles by Von Der Decken, A.

Peptidyl Transferase Activity in Rat Skeletal Muscle Ribosomes After Protein Restriction¹

The Wenner-Gren Institute for Experimental Biology, Stockholm, Sweden

Rats were fed for 6 consecutive days a diet containing casein supplemented with 3 g/kg methionine. The protein level was either 20% or 3%. Skeletal muscle ribosomes were isolated and the activity of the ribosomal enzyme peptidyl transferase was determined. [³H]puromycin acted as acceptor for tRNA bound peptide provided it was located at the ribosomal peptidyl site. The results showed that the rate of peptidyl transferase activity was 13% lower after protein restriction. The differences amounted to 6% when diphtheria toxin and NAD were added as an inhibitor of elongation factor 2. This factor catalyzes translocation of peptidyl-tRNA from ribosomal acceptor to peptidyl site. Between 0.11 and 0.15 pmoles peptidyl-tRNA per pmole ribosome were originally accessable as a substrate for peptidyl transferase. The results indicate that peptidyl transferase contributes to a decrease in protein synthesis after protein restriction; but that other components also contribute to the decrease observed.

KEY WORDS: • protein diet • rat • skeletal muscle • ribosomes • peptidyl transferase • eukaryotes

¹ Supported by a grant from The Swedish Medical Research Council (Proj. No. 4966).

Manuscript received 15 November 1976.