title: The Nitrilase ZmNIT2 converts indole-3-acetonitrile to indole-3-acetic acid.
abstract: We isolated two nitrilase genes, ZmNIT1 and ZmNIT2, from maize (Zea mays) that share 75% sequence identity on the amino acid level. Despite the relatively high homology to Arabidopsis NIT4, ZmNIT2 shows no activity toward beta-cyano-alanine, the substrate of Arabidopsis NIT4, but instead hydrolyzes indole-3-acetonitrile (IAN) to indole-3-acetic acid (IAA). ZmNIT2 converts IAN to IAA at least seven to 20 times more efficiently than AtNIT1/2/3. Quantitative real-time polymerase chain reaction revealed the gene expression of both nitrilases in maize kernels where high concentrations of IAA are synthesized tryptophan dependently. Nitrilase protein and endogenous nitrilase activity are present in maize kernels together with the substrate IAN. These results suggest a role for ZmNIT2 in auxin biosynthesis.
authors.affiliation: Lehrstuhl für Genetik, Technische Universität München, D-85350 Freising, Germany.
authors.forename: Woong June
authors.initials: WJ
authors.lastname: Park
authors.forename: Verena
authors.initials: V
authors.lastname: Kriechbaumer
authors.forename: Axel
authors.initials: A
authors.lastname: Möller
authors.forename: Markus
authors.initials: M
authors.lastname: Piotrowski
authors.forename: Robert B
authors.initials: RB
authors.lastname: Meeley
authors.forename: Alfons
authors.initials: A
authors.lastname: Gierl
authors.forename: Erich
authors.initials: E
authors.lastname: Glawischnig
mesh_terms: D000619:Aminohydrolases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D007210:Indoleacetic Acids / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012639:Seeds / Q000201:enzymology; D013379:Substrate Specificity; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
chemical_list: D007210:Indoleacetic Acids; D007211:Indoles; D007527:Isoenzymes; D011994:Recombinant Proteins; C030737:indoleacetic acid; C016516:indole-3-acetonitrile; D000619:Aminohydrolases; C021867:nitrilase