The Photochemical Inactivation of Peptidyl Transferase Activity

Abstract
The photochemical oxidation of the 50‐S ribosomal subunit results in a rapid irreversible loss of peptidyl transferase activity. The first‐order rate of inactivation occurring during the first forty minutes suggests that a single reactive group is being inactivated. The pH profile of inactivation exhibits a maximum at pH 7.5.Erythromycin at a low concentration (0.04 μmol) affords significant protection. Puromycin also exerts a protective effect but at higher concentrations. Chloramphenicol, sparsomycin and lincomycin did not exert a protective effect.The loss in catalytic activity was not accompanied by a loss in substrate binding affinity of the donor and acceptor substrates.