title: Regulation of amino acid synthetic enzymes in Neurospora crassa in the presence of high concentrations of amino acids.
abstract: Ornithine carbamoyl transferase and leucine aminotransferase of Neurospora crassa represent two of many amino acid synthetic enzymes which are regulated through cross-pathway (or general) amino acid control. In the wild-type strain both enzymes display derepressed activities if the growth medium is supplemented with high (mM range) concentrations of L-amino acids derived from branched pathways, i.e. the aspartate, pyruvate, glycerophosphate and aromatic families of amino acids. A cpc-1 mutant strain, impaired in cross-pathway regulation i.e. lacking the ability to derepress, shows delayed growth under such conditions. In the presence of glycine, homoserine and isoleucine various cpc-1 isolates do not grow at all. Derepression of the wild-type enzymes and the retarded growth of the mutant strain can be reversed if certain amino acids are present in the medium in addition to the inhibitory amino acids.
mesh_terms: D000596:Amino Acids / Q000494:pharmacology*; D007700:Kinetics; D051276:Leucine Transaminase; D009491:Neurospora / Q000201:enzymology*; D009492:Neurospora crassa / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D009954:Ornithine Carbamoyltransferase / Q000378:metabolism*; D000637:Transaminases / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D009954:Ornithine Carbamoyltransferase; D000637:Transaminases; D051276:Leucine Transaminase