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Lookup NU author(s): Dimitra Chormova, Dr Lenka Frankova
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Small molecules (xenobiotics) that inhibit cell-wall-localised enzymes are valuable for elucidating the enzymes' biological roles. We applied a high-throughput fluorescent dot-blot screen to search tor inhibitors of Petroselinum xyloglucan endotransglucosylase (XET) activity in vitro. Of 4216 xenobiotics tested, with cellulose-bound xyloglucan as donor-substrate, 18 inhibited XET activity and 18 promoted, it (especially anthraquinones and flavonoids). No compounds promoted XET in quantitative assays with (cellulose-free) soluble xyloglucan as substrate, suggesting that promotion was dependent on enzymecellulose interactions. With cellulose-free xyloglucan as substrate, we found 22 XET-inhibitors - especially compounds that generate singlet oxygen (O-1(2)) e.g., riboflavin (IC50 29 mu M), retinoic acid, eosin (IC50 27 mu M) and erythrosin (IC50 361 mu M). The riboflavin effect was light-dependent, supporting O-1(2) involvement. Other inhibitors included tannins, sulphydryl reagents and triphenylmethanes. Some inhibitors (vulpinic acid and brilliant blue G) were relatively specific to XET, affecting only two or three, respectively, of nine other wall-enzyme activities tested; others [e.g. (-)-epigallocatechin gallate and riboflavin] were non-specific. In vivo, out of eight XET-inhibitors bioassayed, erythrosin (1 mu M) inhibited cell expansion in Rosa and Zea cell-suspension cultures, and 40 mu M mycophenolic acid and (-)-epigallocatechin gallate inhibited Zea culture growth. Our work showcases a general high-throughput strategy for discovering wall-enzyme inhibitors, some being plant growth inhibitors potentially valuable as physiological tools or herbicide leads. (C) 2015 The Authors. Published by Elsevier Ltd.
Author(s): Chormova D, Franková L, Fry SC
Publication type: Article
Publication status: Published
Journal: Phytochemistry
Year: 2015
Volume: 117
Pages: 220-236
Print publication date: 01/09/2015
Online publication date: 19/06/2015
Acceptance date: 10/06/2015
Date deposited: 23/03/2018
ISSN (print): 0031-9422
ISSN (electronic): 1873-3700
Publisher: Pergamon Press
URL: https://doi.org/10.1016/j.phytochem.2015.06.016
DOI: 10.1016/j.phytochem.2015.06.016
PubMed id: 26093490
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