Induction and repression of L-arabinose isomerase in Salmonella typhimurium.
As with other inducible enzymes, the induced synthesis of l-arabinose isomerase (l-arabinose ketol isomerase, EC 5.3.1.4) in Salmonella typhimurium is subject to catabolite repression. Of the three catabolite repressors tested, glucose produces maximum repression. Analogues of catabolite repressors like 2-deoxy-d-glucose and d-fucose also inhibit the synthesis of the enzyme. The catabolite repression is completely reversed in the presence of 1.5 x 10(-3)m cyclic 3',5'-adenosine monophosphate (AMP). The maximum repression is produced in glucose-grown cells in glucose-containing induction medium. Cyclic 3',5-AMP reverses this repression provided that the cells are treated with ethylenediaminetetraacetic acid (EDTA). In normal cells, cyclic 3',5'-AMP has no effect on the induction but in EDTA-treated cells the cyclic nucleotide enhances synthesis of the enzyme. The inhibition produced by d-fucose cannot be reversed by cyclic 3',5'-AMP. d-Fucose competes with the inducer l-arabinose in some step(s) involved in the process of induction.
D002474:Cell-Free System; D003124:Colorimetry; D003470:Culture Media; D000242:Cyclic AMP / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D004794:Enzyme Repression / Q000187:drug effects; D005643:Fucose / Q000494:pharmacology; D005690:Galactose / Q000494:pharmacology; D005827:Genetics, Microbial; D005947:Glucose / Q000494:pharmacology; D007535:Isomerases / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development
D003470:Culture Media; D005643:Fucose; D004492:Edetic Acid; D000242:Cyclic AMP; D007535:Isomerases; D005947:Glucose; D005690:Galactose