The Isozymic Similarity of Indoleacetic Acid Oxidase to Peroxidase in Birch and Horseradish

Abstract

The relationship of indoleacetic acid oxidase activity to peroxidase activity is complicated by numerous multiple forms of this enzyme system. It is not known if all isozymes of this complex system contain both types of activity. Isozyme analysis of commercial horseradish peroxidase and leaf extracts of yellow birch (Betula alleghaniensis) by isoelectric focusing in polyacrylamide gels was used to examine this problem. Horseradish and birch exhibited 20 and 13 peroxidase isozymes, respectively, by staining with benzidine or scopoletin. Guaiacol was less sensitive. Indoleacetic acid oxidase staining (dimethylaminocinnamaldehyde) generally showed fewer bands, and left doubt as to the residence of both types of activity on all isozymes. Elution of the isozymes from the gels and wet assays verified that all peroxidase isozymes contained indoleacetic acid oxidase activity as well. Estimation of oxidase to peroxidase ratios for the major bands indicated small differences in this parameter. A unique isozyme for one or the other type of activity was not found.

An examination of the peroxidases from Lupinus albus L. hypocotyls

“…Zymograms were developed using either guaiacol, coniferyl alcohol, ferulic acid (Barcel6 et al 1987) or IAA (Gove and Hoyle 1975) as substrates.…”

Elevated indole-3-acetic acid peroxidase activity is involved in the cadmium-induced hydrogen peroxide production in barley root tip

“…It has previously been observed in different plant species, that several isoforms of PODs contained IAA oxidase activity as well (Gove and Hoyle 1975;Hoyle 1977;Gazaryan et al 1999). The activity of typical soluble auxinoxidases was dependent on the presence of cofactors, such as MnCl 2 and phenols (Beffa et al 1990).…”

The susceptibility of plants to Agrobacterium: A discussion of the role of phenolic compounds

“…an inhibitory effect on the enzymatic oxidation of fl-indole-3-acetic acid (IAA). In general, monophenols and meta-diphenols act as cofactors or activators, whereas orthoand para-diphenols and polyphenols inhibit IAA oxidase or induce a lag period [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. Thus, caffeic acid, catechol and chlorogenic acid inhibit IAA oxidase activity, whereas p-, m-, o-coumaric acid and p-hydroxybenzoic acid activate its activity.…”