title: Aspartokinase isoenzymes of the fruiting myxobacterium Myxoccus xanthus.
abstract: Two isoenzymes of aspartokinase can be found in extracts of the differentiating bacterium Myxococcus xanthus. Aspartokinase I is repressed by L-lysine and feedback is inhibited by meso-diaminopimelate and by low concentrations of L-lysine. However, the inhibition by L-lysine is no longer observed at high concentration of this amino acid. Aspartokinase II is repressed and feedback inhibited specifically by L-threonine. Both enzymes are stimulated significantly by L-methionine and L-isoleucine; the effect is greater with aspartokinase I. The role of these enzymes in relation to growth conditions of the organism is discussed and a correlation with life cycle activity is indicated.
mesh_terms: D001222:Aspartate Kinase / Q000302:isolation & purification / Q000378:metabolism*; D002455:Cell Division; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007532:Isoleucine / Q000494:pharmacology; D007700:Kinetics; D008239:Lysine / Q000494:pharmacology; D008715:Methionine / Q000494:pharmacology; D009231:Myxococcales / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D010770:Phosphotransferases / Q000378:metabolism*; D013912:Threonine / Q000494:pharmacology
chemical_list: D007527:Isoenzymes; D007532:Isoleucine; D013912:Threonine; D008715:Methionine; D010770:Phosphotransferases; D001222:Aspartate Kinase; D008239:Lysine