Enzymic synthesis of 1-O-indol-3-ylacetyl-beta-D-glucose and indol-3-ylacetyl-myo-inositol

Biochem J. 1982 Nov 1;207(2):273-81. doi: 10.1042/bj2070273.


An enzyme fraction from extracts of immature kernels of Zea mays catalyses the formation of 1-O-indol-3-ylacetyl-beta-D-glucose from indol-3-ylacetic acid and UDP-glucose. A second enzyme fraction catalyses the formation of indol-3-ylacetyl-myo-inositol from 1-O-indol-3-ylacetyl-beta-D-glucose and myo-inositol. To our knowledge, this is the first example of hydroxy-group acylation by a 1-O-acyl sugar. The following reaction sequence is proposed: Indol-3-ylacetic acid + UDP-glucose leads to indol-3-ylacetylglucose + UDP (1) Indol-3-ylacetylglucose + myo-inositol leads to indol-3-ylacetyl-myo-inositol + glucose (2) The enzyme catalysing reaction (1) is called UDP-glucose:indol-3-ylacetate glucosyl-transferase (indol-3-ylacetylglucose synthase), and that catalysing reaction (2) is indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (indol-3-ylacetyl-myo-inositol synthase). We further show that indol-3-ylacetylglucose synthase is specific for UDP-glucose and, at the stage of purity tested, the enzyme will use either indol-3-ylacetic acid or naphthalene-1-acetic acid, but not 2.4-dichlorophenoxyacetic acid, as glucose acceptor. The indol-3-ylacetyl-myo-inositol synthase is specific for indol-3-ylacetyl-glucose and will not use naphthalene-1-acetylglucose as substrate, and it is specific for myo-inositol among the alcohol acceptors tested. Thus, of the auxins tested, only indol-3-ylacetic acid forms the myo-inositol ester.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acyltransferases / metabolism
  • Glucosyltransferases / metabolism
  • Indoleacetic Acids / metabolism*
  • Kinetics
  • Magnesium / metabolism
  • Plants / enzymology*
  • Substrate Specificity
  • Uridine Diphosphate Glucose / metabolism
  • Uridine Triphosphate / metabolism
  • Zea mays / enzymology


  • Indoleacetic Acids
  • 1-O-indol-3-ylacetylglucose
  • indol-3-ylacetylinositol
  • Acyltransferases
  • indoleacetyl-glucose-myo-inositol indoleacetyl transferase
  • Glucosyltransferases
  • indole-3-acetate beta-glucosyltransferase
  • Magnesium
  • Uridine Triphosphate
  • Uridine Diphosphate Glucose