title: Synthesis and biological activity of amino acid conjugates of abscisic acid.
abstract: We prepared 19 amino acid conjugates of the plant hormone abscisic acid (ABA) and investigated their biological activity, enzymatic hydrolysis by a recombinant Arabidopsis amidohydrolases GST-ILR1 and GST-IAR3, and metabolic fate in rice seedlings. Different sets of ABA-amino acids induced ABA-like responses in different plants. Some ABA-amino acids, including some that were active in bioassays, were hydrolyzed by recombinant Arabidopsis GST-IAR3, although GST-ILR1 did not show hydrolysis activity for any of the ABA-amino acids. ABA-L-Ala, which was active in all the bioassays, an Arabidopsis seed germination, spinach seed germination, and rice seedling elongation assays, except in a lettuce seed germination assay and was hydrolyzed by GST-IAR3, was hydrolyzed to free ABA in rice seedlings. These findings suggest that some plant amidohydrolases hydrolyze some ABA-amino acid conjugates. Because our study indicates the possibility that different plants have hydrolyzing activity toward different ABA-amino acids, an ABA-amino acid may function as a species-selective pro-hormone of ABA.
authors.affiliation: Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan. aytodor@ipc.shizuoka.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Todoroki
authors.forename: Kenta
authors.initials: K
authors.lastname: Narita
authors.forename: Taku
authors.initials: T
authors.lastname: Muramatsu
authors.forename: Hajime
authors.initials: H
authors.lastname: Shimomura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Masaharu
authors.initials: M
authors.lastname: Mizutani
authors.forename: Kotomi
authors.initials: K
authors.lastname: Ueno
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Hirai
mesh_terms: D000040:Abscisic Acid / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D029681:Arabidopsis Proteins / Q000378:metabolism; D018525:Germination; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D012275:Oryza / Q000378:metabolism; D010937:Plant Growth Regulators / Q000737:chemistry / Q000378:metabolism; D012639:Seeds / Q000254:growth & development; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000596:Amino Acids; D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D000040:Abscisic Acid