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Amidase Activity in Soils: IV. Effects of Trace Elements and Pesticides
Author(s) -
Frankenberger W. T.,
Tabatabai M. A.
Publication year - 1981
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1981.03615995004500060021x
Subject(s) - chemistry , soil water , amidase , trifluralin , environmental chemistry , alachlor , pesticide , nuclear chemistry , atrazine , enzyme , agronomy , biochemistry , biology , ecology
Amidase was recently detected in soils, and this study was carried out to assess the effects of 21 trace elements, 12 herbicides, 2 fungicides, and 2 insecticides on the activity of this enzyme. Results showed that most of the trace elements and pesticides studied inhibited amidase activity in soils. The degree of inhibition varied among the soils used. When the trace elements were compared by using 5 µmol/g of soil, the average inhibition of amidase in three soils showed that Ag(I), Hg(II), As(III), and Se(IV) were the most effective Inhibitors, but only Ag(I) and As(III) showed average inhibition > 50%. The least effective inhibitors (average inhibition < 3%) included Cu(I), Ba(II), Cu(II), Fe(II), Ni(II), Al(III), Fe(III), Ti(IV), V(IV), As(V), Mo(VI), and W(VI). Other elements that inhibited amidase activity in soils were Cd(II), Co(II), Mn(II), Pb(II), Sn(II), Zn(II), B(III), and Cr(III). Enzyme kinetic studies showed that As(III) was a competitive Inhibitor of amidase, whereas Ag(I), Hg(II), and Se(IV) were noncompetitive inhibitors. When the pesticldes studied were compared by using 10µg of active ingredlent per gram of soil, the average inhibition of amidase in three soils ranged from 2% with dinitroamine, EPTC plus R‐25788, and captan to 10% with butylate. Other pesticides that inhibited amidase activity in soils were atrazine, naptalam, cbloramben, dicamba, cyanazine, 2,4‐D, alachlor, paraquat, trifluralin, maneb, diazinon, and malathion. The inhibition of amidase by diazinon, alachlor, and butylate followed noncompetitive kinetics.