Počet záznamů: 1

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

  1. 1.
    0359306 - UEB-Q 2011 RIV GB eng J - Článek v odborném periodiku
    Frébortová, Jitka - Novák, Ondřej - Frébort, Ivo - Jorda, Radek
    Degradation of cytokinins by maize cytokinin dehydrogenase is mediated by free radicals generated by enzymatic oxidation of natural benzoxazinones.
    Plant Journal. Roč. 61, č. 3 (2010), s. 467-481 ISSN 0960-7412
    Grant CEP: GA ČR GA522/05/0448; GA ČR GA301/08/1649
    Výzkumný záměr: CEZ:AV0Z50380511
    Klíčová slova: Degradation * cytokinins * maize
    Kód oboru RIV: EF - Botanika
    Impakt faktor: 6.948, rok: 2010

    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.
    Trvalý link: http://hdl.handle.net/11104/0197110
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