title: Effects on ribosomes of the substitution of spermidine or divalent cations for magnesium ions.
abstract: The inactivation of rat liver ribosomes (polysomes) resulting from the replacement of bound magnesium by spermidine has been studied using a dialysis method. Inactivation of the ribosomes (polysomes) occurred when more than 40% of the Mg2+ originally bound to ribosomes in the presence of 2 mM Mg2+ was replaced by spermidine. The polypeptide-synthesizing activity of polysomes was retained partially when Mg2+ was replaced by Mn2+ by dialysis. E. coli 30S ribosomal subunits were more resistant to inactivation due to the replacement of Mg2+ by spermidine than the 50S subunits.
mesh_terms: D000818:Animals; D002413:Cations, Divalent; D003956:Dialysis; D004926:Escherichia coli / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism; D010452:Peptide Biosynthesis; D011132:Polyribosomes / Q000378:metabolism; D051381:Rats; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism*; D013095:Spermidine / Q000494:pharmacology*
chemical_list: D002413:Cations, Divalent; D008345:Manganese; D008274:Magnesium; D013095:Spermidine