62
Richard H. Shimabukuro et al.
CYANAZINE
Figure 2.24. Metabolism of cyanazine by glutathione conjugation in com and rats.
GSH conjugation and catabolism of fturodifen occurred in both mammals
(Lamoureux and Davison, 1975) and plants (Fig. 2.25) (Shimabukuro et al.,
1973a). The initial GSH-dependent cleavage of the diphenylether as catalyzed
by a glutathione S-aryl transferase from rat liver (Lamoureux and Davison, 1975),
and from several plant species (Frear and Swanson, 1973). In rats the resultant
mercapturic acid was excreted in the urine (Lamoureux and Davison, 1975).
However, unlike atrazine in sorghum (Fig. 2.23) ftuorodifen was not metabolized
to its lanthionine conjugate. Instead, the S-cysteine conjugate of ftuorodifen was
acylated in peanuts to yield S-(2-nitr0-4-triftuoromethylphenyl)-N-malonylcysteine, an analog of the N-acetylated mercapturic acid (Shimabukuro et aI., 1976b).
Other herbicides known to be metabolized by GSH conjugation are propachlor (Lamoureux et al., 1971), CDAA (Lamoureux et al., 1971), and barban
(Fig. 2.26) (Lamoureux et al., 1971; Shimabukuro et al., 19700). The 'Y-glutamylcysteine conjugate of propachlor was characterized in com (Lamoureux et
al., 1971), but the mercapturic acids of propachlor and CDAA were identified
only in the rat (Lamoureux and Davison, 1975). In vitro and in vivo conjugation
with glutathione occurred with the fungicide PeNB in peas (Fig. 2.26) (Lamoureux and Rusness, 1976) and the aryl hydroxylated metabolites of chlorpropham (Fig. 2.27) and cisanilide in oats (Rusness and Still, 1977).
Direct conjugation of 4-hydroxychlorpropham with cysteine was also demonstrated (Fig. 2.27) (Still and Rusness, 1977). Conjugation occurred enzymatically without the loss of either the halogen or the hydroxyl group. The
Richard H. Shimabukuro et al.
CYANAZINE
Figure 2.24. Metabolism of cyanazine by glutathione conjugation in com and rats.
GSH conjugation and catabolism of fturodifen occurred in both mammals
(Lamoureux and Davison, 1975) and plants (Fig. 2.25) (Shimabukuro et al.,
1973a). The initial GSH-dependent cleavage of the diphenylether as catalyzed
by a glutathione S-aryl transferase from rat liver (Lamoureux and Davison, 1975),
and from several plant species (Frear and Swanson, 1973). In rats the resultant
mercapturic acid was excreted in the urine (Lamoureux and Davison, 1975).
However, unlike atrazine in sorghum (Fig. 2.23) ftuorodifen was not metabolized
to its lanthionine conjugate. Instead, the S-cysteine conjugate of ftuorodifen was
acylated in peanuts to yield S-(2-nitr0-4-triftuoromethylphenyl)-N-malonylcysteine, an analog of the N-acetylated mercapturic acid (Shimabukuro et aI., 1976b).
Other herbicides known to be metabolized by GSH conjugation are propachlor (Lamoureux et al., 1971), CDAA (Lamoureux et al., 1971), and barban
(Fig. 2.26) (Lamoureux et al., 1971; Shimabukuro et al., 19700). The 'Y-glutamylcysteine conjugate of propachlor was characterized in com (Lamoureux et
al., 1971), but the mercapturic acids of propachlor and CDAA were identified
only in the rat (Lamoureux and Davison, 1975). In vitro and in vivo conjugation
with glutathione occurred with the fungicide PeNB in peas (Fig. 2.26) (Lamoureux and Rusness, 1976) and the aryl hydroxylated metabolites of chlorpropham (Fig. 2.27) and cisanilide in oats (Rusness and Still, 1977).
Direct conjugation of 4-hydroxychlorpropham with cysteine was also demonstrated (Fig. 2.27) (Still and Rusness, 1977). Conjugation occurred enzymatically without the loss of either the halogen or the hydroxyl group. The