Open AccessPeptidyl-Puromycin Synthesis on Polyribosomes from Escherichia coli
Author(s) -
Sidney Pestka
Publication year - 1972
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.69.3.624
Subject(s) - puromycin , escherichia coli , polysome , ribosome , protein biosynthesis , chemistry , translation (biology) , biochemistry , biology , rna , messenger rna , gene
Peptide bond synthesis was studied with native polyribosomes ofE. coli . With the use of this system for transpeptidation, it was possible to show that a single K+ activates the ribosome monomers of polyribosomes; that protonation of a single group (probably imidazole or an N-terminal amino group) with a pKa equal to about 7.2 inactivates the transpeptidase complex; that Mn++ can substitute for Mg++ , but that Ca++ , spermidine, and putrescine do so only very poorly; and that theKm for puromycin in this system is about 2.4 × 10-6 M.