Met-tRNA _f ^Met Binding to 40S Ribosomal Subunits: A Site for the Regulation of Initiation of Protein Synthesis by Hemin

Abstract

ABSTRACT

Ricin B chain converts a non‐cytotoxic antibody‐ricin A chain conjugate into a potent and specific cytotoxic agent

“…The capacity of the A chain to inhibit ribosomai protein synthesis after conjugation to the antibody was assayed in a rabbit reticulocyte cell-free system [7] and found to be unimpaired. Binding of the conjugate was assessed by the measurement of iz51-labelled sheep anti-rat y 2 on the target cells.…”

Studies of a factor from dystrophic mouse muscle inhibitory towards protein synthesis

“…The haemin-regulated inhibitor, double-stranded RNA, oxidized glutathione and the inhibitor found in lysates prepared from leukaemic cells all inhibit initiation of protein synthesis (Legon et al, 1974;Cimadevilla & Hardesty, 1975) and thus are different from the inhibitor found in muscle. Moreover the haemin-regulated inhibitor has no effect on poly(U)-directed protein synthesis (Clemens et al, 1974). Furthermore, the addition of haemin to our incubation assay does not remove the inhibitory activity.…”

Association of initiation factor eIF-2 with a rapidly sedimenting fraction from Ehrlich ascites-tumour cells

“…The polypeptide-chain-initiation factor eIF-2 has been implicated in several examples of translational control of protein synthesis in animal cells (Clemens et al, 1974;Lebleu et al, 1976;Farrell et al, 1977;Kay et al, 1979;Pain et al, 1980; see also review by Austin & Clemens, 1980). We have shown that starvation of Ehrlich ascites-tumour cells for a single essential amino acid results in inhibition of initiationcomplex formation on native 40S ribosomal subunits both in intact cells (Pain & Henshaw, 1975) and in extracts prepared from them .…”