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Inertness of horseradish peroxidase to 2,4‐dichlorophenoxyacetic acid
Author(s) -
PAUL K. G.,
ÖHRMAN B.
Publication year - 1980
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1980.tb02649.x
Subject(s) - horseradish peroxidase , guaiacol , peroxidase , chemistry , catechol , catalysis , catechol oxidase , nuclear chemistry , oxidase test , enzyme , chromatography , biochemistry , polyphenol oxidase
The possibility of mutual effects of 2,4‐D and horseradish ( Armoracia lapathifolia L.) peroxidase on each other has been explored by four procedures. (i) Compounds I, II, and III of horseradish peroxidase (HRP) and H 2 O 2 were exposed to 2,4‐D. (ii) Extracts from batchwise operations of HRP + H 2 O 2 and 2,4‐D were analyzed for oxidation products by means of thin layer chromatography. (iii) The velocity of the IAA oxidase reaction with HRP as catalyst, and (iv) K m and V s of the overall peroxidation of guaiacol by HRP + H 2 O 2 , were determined in the absence and presence of 2,4‐D. The results failed to show any effect of 2,4‐D; only at very high concentrations did 2,4‐D slightly inhibit the oxidation of IAA by one isoperoxidase. It is concluded that 2,4‐D does not promote growth in plants by hampering a peroxidase‐catalyzed IAA oxidation. It seems probable that 2,4‐D perturbs the isoperoxidase pattern by acting at some step prior to the release of the enzyme from its site of synthesis.