title: Effect of ABA-beta-D-glucopyranosyl ester and activity of ABA-beta-D-glucosidase in Arabidopsis thaliana.
abstract: Exogenously applied ABA-beta-D-glucopyranosyl ester (ABA-GE) inhibited hypocotyl growth of Arabidopsis seedlings at concentrations greater than 0.3 micromol/L, and the concentration for 50% inhibition of hypocotyl growth was 1.8 micromol/L. ABA-beta-D-glucosidase activity in Arabidopsis seedlings was 17 nmol/mg protein/mim and increased by exogenously applied ABA-GE. The pH optimum of this enzyme in crude extract of Arabidopsis seedlings was 6.0 for the assay in the ABA-GE to ABA direction and its K(m) value for ABA-GE (pH 6.0) was 0.41 mmol/L. These results suggests that exogenously applied ABA-GE may be absorbed by roots and hydrolyzed by ABA-beta-D-glucosidase and librated free ABA may induce growth inhibition in Arabidopsis hypocotyls.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan. hisashi@ag.kagawa-u.ac.jp
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kato-Noguchi
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000040:Abscisic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects* / Q000201:enzymology*; D018546:Hypocotyl / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D001617:beta-Glucosidase / Q000378:metabolism*
chemical_list: C488692:abscisic acid-beta-D-glucopyranosyl ester; D000040:Abscisic Acid; D001617:beta-Glucosidase