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SC‐0051, a 2‐benzoyl‐cyclohexane‐1,3‐dione bleaching herbicide, is a potent inhibitor of the enzyme p ‐hydroxyphenylpyruvate dioxygenase
Author(s) -
Schulz Arno,
Ort Oswald,
Beyer Peter,
Kleinig Hans
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80013-k
Subject(s) - homogentisic acid , biochemistry , chemistry , tyrosine , enzyme , quinone , biosynthesis
Growth inhibition of Lemna gibba plantlets by the bleaching herbicide, SC‐0051 (2‐(2‐chloro‐4‐methanesulfonylbenzoyl)‐1,3‐cyclohexanedione)) was alleviated by the addition of homogentisic acid to the growth medium. Homogentisic acid is a key intermediate in the biosynthesis of tyrosine‐derived plant quinones as well as in tyrosine metabolism. The herbicide prevented the incorporation of radioactivity from [ 14 C]tyrosine into lipophilic plant metabolites and, in rat liver extracts, the herbicide inhibited the conversion of tyrosine to homogentisic acid. The enzyme p ‐hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27) from both Zea mays seedlings and liver tissues, was found to be subject to strong inhibition by SC‐0051. Inhibition of plant quinone biosynthesis is a new mode of herbicidal action. One of the consequences of quinone depletion in plants in vivo is apparently an indirect inhibition of phytoene desaturation. The enzyme phytoene desaturase itself, however, is not afflicted by the herbicide.