Inhibition of acetyl-coenzyme A carboxylase by two classes of grass-selective herbicides

Journal Article · Tue May 01 00:00:00 EDT 1990 · Journal of Agricultural and Food Chemistry; (USA)

DOI:https://doi.org/10.1021/jf00095a029· OSTI ID:6321155

Rendina, A R; Craig-Kennard, A C; Beaudoin, J D; Breen, M K ^[1]

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1. Chevron Chemical Company, Richmond, CA (USA)

The selective grass herbicides diclofop, haloxyfop, and trifop (((aryloxy)phenoxy)propionic acids) and alloxydim, sethoxydim, and clethodim (cyclohexanediones) are potent, reversible inhibitors of acetyl-coenzyme A carboxylase (ACC) partially purified from barley, corn, and wheat. Although inhibition of the wheat enzyme by clethodim and diclofop is noncompetitive versus each of the substrates adenosine triphosphate (ATP), HCO{sub 3}{sup {minus}}, and acetyl-coenzyme A (acetyl-CoA), diclofop and clethodim are nearly competitive versus acetyl-CoA since the level of inhibition is most sensitive to the concentration of acetyl-CoA (K{sub is} < K{sub ii}). To conclusively show whether the herbicides interact at the biotin carboxylation site or the carboxyl transfer site, the inhibition of isotope exchange and partial reactions catalyzed at each site was studied with the wheat enzyme. Only the ({sup 14}C)acetyl-CoA-malonyl-CoA exchange and decarboxylation of ({sup 14}C)malonyl-CoA reactions are strongly inhibited by clethodim and diclofop, suggesting that the herbicides interfere with the carboxyl transfer site rather than the biotin carboxylation site of the enzyme. Double-inhibition studies with diclofop and clethodim suggest that the ((aryloxy)phenoxy)propionic acid and cyclohexanedione herbicides may bind to the same region of the enzyme.

• OSTI ID: 6321155
• Journal Information: Journal of Agricultural and Food Chemistry; (USA), Vol. 38:5; ISSN 0021-8561
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
CARBOXYLASE
BIOCHEMICAL REACTION KINETICS
HERBICIDES
BIOLOGICAL EFFECTS
BARLEY
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
ENZYME ACTIVITY
INHIBITION
MAIZE
WHEAT
CARBON-CARBON LYASES
CARBOXY-LYASES
CEREALS
ENZYMES
GRAMINEAE
KINETICS
LABELLED COMPOUNDS
LILIOPSIDA
LYASES
MAGNOLIOPHYTA
ORGANIC ACIDS
ORGANIC COMPOUNDS
PESTICIDES
PLANTS
REACTION KINETICS
553003* - Agriculture &amp; Food Technology- Pest &amp; Disease Control- (1987-)