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Degradation of cytokinins by maize cytokinin dehydrogenase is mediated by free radicals generated by enzymatic oxidation of natural benzoxazinones

SYSNO ASEP	0359306
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Degradation of cytokinins by maize cytokinin dehydrogenase is mediated by free radicals generated by enzymatic oxidation of natural benzoxazinones
Author(s)	Frébortová, Jitka (UEB-Q)_{RID, ORCID} Novák, Ondřej (UEB-Q)_{RID, ORCID, SAI} Frébort, Ivo (UEB-Q) Jorda, Radek (UEB-Q)_{ORCID, RID}
Number of authors	4
Source Title	Plant Journal. - : Wiley - ISSN 0960-7412 Roč. 61, č. 3 (2010), s. 467-481
Number of pages	15 s.
Language	eng - English
Country	GB - United Kingdom
Keywords	Degradation ; cytokinins ; maize
Subject RIV	EF - Botanics
R&D Projects	GA522/05/0448 GA ČR - Czech Science Foundation (CSF)
	GA301/08/1649 GA ČR - Czech Science Foundation (CSF)
CEZ	AV0Z50380511 - UEB-Q (2005-2011)
UT WOS	000273911800009
DOI	10.1111/j.1365-313X.2009.04071.x
Annotation	Hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-one (DIMBOA) was isolated from maize phloem sap as a compound enhancing the degradation of isopentenyl adenine by maize cytokinin dehydrogenase (CKX), after oxidative conversion by either laccase or peroxidase. Laccase and peroxidase catalyze oxidative cleavage of DIMBOA to 4-nitrosoresorcinol-1-monomethyl ether (coniferron), which serves as a weak electron acceptor of CKX. The oxidation of DIMBOA and coniferron generates transitional free radicals that are used by CKX as effective electron acceptors. The function of free radicals in the CKX-catalyzed reaction was also verified with a stable free radical of 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid. Application of exogenous cytokinin to maize seedlings resulted in an enhanced benzoxazinoid content in maize phloem sap. The results indicate a new function for DIMBOA in the metabolism of the cytokinin group of plant hormones.
Workplace	Institute of Experimental Botany
Contact	David Klier, knihovna@ueb.cas.cz, Tel.: 220 390 469
Year of Publishing	2011

Number of the records: 1