title: Cellular location of peroxidase isoenzymes in leaf tissue of Petunia and their affinity for Concanavalin A-Sepharose.
abstract: The cellular location of three peroxidase isoenzymes (PRX) in mature leaf tissue of Petunia and their affinity for Concanavalin A-Sepharose were investigated. The isoenzymes PRXa, PRXb and PRXc were identified by their positions in starch-gel zymograms. The fast-moving anodic and cathodic peroxidase bands, the isoenzymes PRXa and PRXc respectively, were the most active peroxidases in extracellular extracts. The molecular forms of PRXa showed a tissue-specific distribution between midrib and remaining leaf tissue. An intermediate-moving anodic peroxidase band, the isoenzyme PRXb, was the most active peroxidase released after extraction of isolated mesophyll protoplasts. Small amounts of the peroxidase isoenzymes were present in cell-wall-bound fractions. Incubation of a crude protein fraction with Concanavalin A-Sepharose showed that the isoenzyme PRXb bound more firmly to Concanavalin A-Sepharose than the isoenzymes PRXa and PRXc, of which only one molecular form bound partly. The results are discussed with respect to a possible function of one of the peroxidase isoenzymes, and a possible role of oligosaccharide chains in determining the cellular location of plant peroxidases is suggested.
authors.affiliation: Vakgroep Genetica, Genetisch Institut der Universiteit, Kruislaan 318, NL-1098 SM, Amsterdam, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Hendriks
authors.forename: B M
authors.initials: BM
authors.lastname: van den Berg
authors.forename: A W
authors.initials: AW
authors.lastname: Schram