title: Action of thiazolidine-2-carboxylic acid, a proline analog, on protein synthesizing systems.
abstract: Thiazolidine-2-carboxylic acid, or beta-thiaproline, is a proline analog in which the beta methylene group of proline is substituted by a sulfur atom. It has been deomonstrated that beta-thiaproline is activated and transferred to tRNAPro by Escherichia coli and rat liver aminoacyl-tRNA synthetases, and inhibits proline incorporation into polypeptides in protein synthesizing systems from E. coli, rat liver or rabbit reticulocytes. In mammalian systems beta-thiaproline inhibits also leucine incorporation; in rabbit reticulocyte lysate it inhibits ribosome run-off. Both these effects may be explained by the fact that beta-thiaproline once incorporated into the growing polypeptide chain impairs its further elongation, as shown by experiments made with puromycin. All tests were performed in comparison with thiazolidine-4-carboxylic acid, or gamma-thiaproline, another proline analog having the gamma methylene group substituted by a sulfur atom; it was shown that in all the reactions studied both compounds act as competitive inhibitors of proline. Some differences in the effects of the two analogs have been evidenced: in almost all the reactions and mainly in the whole protein synthesizing systems, beta-thiaproline shows an higher inhibitory activity.
mesh_terms: D000603:Amino Acids, Sulfur / Q000494:pharmacology; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D011392:Proline / Q000031:analogs & derivatives* / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000187:drug effects*; D011691:Puromycin / Q000494:pharmacology; D012343:RNA, Transfer / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D012156:Reticulocytes / Q000201:enzymology; D053778:Thiazolidines
chemical_list: D000603:Amino Acids, Sulfur; D053778:Thiazolidines; C021760:thiazolidine-2-carboxylic acid; D011691:Puromycin; D012343:RNA, Transfer; D011392:Proline; D000604:Amino Acyl-tRNA Synthetases