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Summary: Résumé: Zusammenfassung Thirty‐eight different agronomic and horticultural crop plants were tested for aryl acylamidase enzymes which could hydrolyse the amide bond of the herbicide, 3′,4′‐dichloropropion‐anilide (propanil). More than half of these plants, from ten different plant families, covering thirty genera, possessed enzymes capable of degrading propanil in this manner. Enzyme preparations from leaf lettuce (Lactuca sativa L.) appeared to be the richest source of aryl acylamidase activity. The total enzyme units present, as well as specific activities of enzymes from these plant tissue preparations, varied widely in the different plants. Hydrotyse du 3′,4′‐dichtoropropionanitide par des aryt acylamytases vegetates. Trente‐huit cultures différentes parmi lesquelles des plantes horticoles ont été essayées quant à la production d'aryl acylamylases, enzymes qui pourraient hydrolyser la liaison amidede l'herbicide 3′,4′‐dichloropropionanilide (propanil). Plus de la moitié de ces plantes appartenant 4 10 families différentes et représentant 30 genres possèdent des enzymes capables de dégrader le propanil de cette maniére. Des préparations enzymatiques effectuées à partir de la feuille de laitue (Lactuca sativa L.) se sont révélées être les sources les plus abondantes d'activité aryl acylamylase. Le total des unités enzymatiques présentes, aussi bien que les activités spécifiques des enzymes extraites de ces préparations de tissus végétaux ont varié de façon importante selon les especes vegétales. Hydrolyse von 3′,4′‐Dichlorpropionanilid durch pflanzliche Arytacytamidasen Es wurden 38 verschiedene landwirtschaftliche und gärtnerische Kulturpflanzen auf Arylacylamidase Enzyme untersucht, die die Amidbindung des Herbizids 3′,4′‐Dichlor‐propionanilid (Propanil) hydrolysieren konnten. Mehr als die Hälfte dieser Pflanzen, aus zehn verschiedenen Pflanzenfamilien, 30 Gattungen einschliessend, enthielten Enzyme, die Propanil auf diese Weise abzubauen vermochten. Enzymprapärationen von Kopfsalat (Lactuca sativa L.) schienen die ergiebigste Quelle für die Arylacylamidase‐Aktivität zu sein. Die insgesamt vorhandenen Enzymeinheiten, als auch die spezifischen Aktivitäten der Enzyme der Gewebepräparationen, schwankten bei den verschiedenen Pflanzen ziemlich stark.

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An amidohydrolase (EC 3.5.1.13) was isolated from the roots of soybean (Glycine max Merril, var. Hawkeye) seedlings and purified 130-fold over the crude extract with 30% recovery. The purification steps entailed ammonium sulfate precipitation, gel filtration, cellulose ion-exchange chromatography, and polyacrylamide gel electrophoresis. The specific activity of the purified enzyme for the hydrolysis of Nα-benzoyl-DL-arginine p-nitroanilide (BAPA) was 810 mU/mg. The Km of the enzyme for this substrate was 5.78 × 10−6 M. The enzyme possessed a broad substrate specificity and catalyzed the hydrolysis of BAPA, glycine p-nitroanilide, L-leucine p-nitroanilide, and L-lysine p-nitroanilide. Specificity studies with a series of aminoacyl β-naphthylamides revealed a high hydrolysis rate on Nα-benzoyl-L-arginine β-naphthylamide, and lower hydrolysis rates on several other aminoacyl-substituted β-naphthylamides. The enzyme also displayed dipeptide hydrolase activity on several dipeptide substrates. The enzyme had a pH optimum of 8.0 in 0.05 M phosphate buffer with Nα-benzoyl-DL-arginine p-nitroanilide as substrate. The temperature optimum was 50 °C. The apparent activation energy determined from an Arrhenius plot was 6.3 kcal/mol (26 400 J/mol). The molecular weight estimated by gel filtration was approximately 63 000. Mercury (II) ion, silver (I) ion, p-benzoquinone, p-chloromercuribenzoate, and N-ethylmaleimide were effective inhibitors of the enzyme.

references cited therein; (d) H. Basch, Theor. Chim. Acta, 28, 151 (1973). We thank Professor C. Trindle (University of Virginia) for this reference.(3) For reviews, see (a) G. L. Closs in Top. Stereochem., 3, 193 (1968); (b) P.

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