Format

Send to

Choose Destination
See comment in PubMed Commons below
Phytochemistry. 2000 Mar;53(5):565-70.

Scission of polysaccharides by peroxidase-generated hydroxyl radicals.

Author information

1
Albert-Ludwigs-Universität Freiburg, Institut für Biologie II, Germany.

Abstract

Cell-wall polysaccharides can be broken down non-enzymatically in vitro by scission of backbone bonds in a Fenton reaction system producing hydroxyl radicals (OH*) (Fry, S.C. (1998). Biochemical Journal, 332, 507-515). OH* can also be generated enzymatically from O2 by horseradish peroxidase (HRP) in a complex reaction cycle involving NADH or dihydroxyfumarate (DHF) as reducing substrate (Chen, S.-X., & Schopfer, P. (1999). European Journal of Biochemistry, 260, 726-735). Based on these recent findings the possibility that HRP can be used to degrade cell-wall polysaccharides in vitro was investigated. The production of OH* from O2 by HRP in the presence of NADH or DHF was confirmed by EPR spectroscopy using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap. Chemical scission of polysaccharides (dextran, pectin, xyloglucan) by HRP-generated OH* was demonstrated using a viscometric assay. The reaction could be inhibited by an array of OH* scavengers, confirming the involvement OH* as the causative agent for macromolecule cleavage. The significance of these findings for the biochemical function of peroxidase in cell-wall loosening processes underlying cell expansion and related physiological processes is discussed.

PMID:
10724181
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center