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Greenberg-Levy, S.H., Department of Stored Products, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
Ishaaya, I., Department of Entomology, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
Shaaya, E., Department of Stored Products, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
Silhacek, D.L., Insect Attractants, Behavior and Basic Biology Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Gainesville, FL, United States
Oberlander, H., Insect Attractants, Behavior and Basic Biology Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Gainesville, FL, United States
The optimal conditions for diflubenzuron hydrolase activity in Plodia interpunctella were determined using [14C]diflubenzuron (DFB) as substrate. The radiolabeled metabolites 4-chloroaniline (4-CA) and 4-chlorophenylurea (4-CPU) were separated and quantitatively evaluated. Profenofos and S, S, S-tributyl phosphorotrithioate inhibited the enzyme activity in vitro, profenofos being more active. Hydrolysis was also inhibited in the presence of p-nitroacetanilide (pNAA), resulting in a 66% decrease in the release of 4-CA; the release of I-CPU was not affected. pNAA hydrolase activity was higher in the prepupa than in the larval stages. Profenofos inhibited pNAA hydrolase activity to a much greater extent than DEF. The enzyme activity was inhibited by DFB at relatively high concentrations. Determination of Michaelis-Menten kinetics with and without DFB revealed typical competitive reversible inhibition plots. The inhibition depended on the concentrations of enzyme, substrate, and inhibitor. Inhibition of pNAA hydrolysis occurred in the presence of DFB or its antibodies. Our findings indicate the possibility of using pNAA as a surrogate substrate for DFB hydrolase activity. The enzyme assay is accurate and easy to perform and may open up new avenues of research aimed at evaluating defense systems and resistance mechanisms to DFB and other benzoylphenyl ureas. © 1995 Academic Press, Inc.
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הספר "אוצר וולקני"
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תנאי שימוש
Hydrolase activity in plodia interpunctella: Use of diflubenzuron and p-nitroacetanilide as substrates
52
Greenberg-Levy, S.H., Department of Stored Products, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
Ishaaya, I., Department of Entomology, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
Shaaya, E., Department of Stored Products, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
Silhacek, D.L., Insect Attractants, Behavior and Basic Biology Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Gainesville, FL, United States
Oberlander, H., Insect Attractants, Behavior and Basic Biology Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Gainesville, FL, United States
Hydrolase activity in plodia interpunctella: Use of diflubenzuron and p-nitroacetanilide as substrates
The optimal conditions for diflubenzuron hydrolase activity in Plodia interpunctella were determined using [14C]diflubenzuron (DFB) as substrate. The radiolabeled metabolites 4-chloroaniline (4-CA) and 4-chlorophenylurea (4-CPU) were separated and quantitatively evaluated. Profenofos and S, S, S-tributyl phosphorotrithioate inhibited the enzyme activity in vitro, profenofos being more active. Hydrolysis was also inhibited in the presence of p-nitroacetanilide (pNAA), resulting in a 66% decrease in the release of 4-CA; the release of I-CPU was not affected. pNAA hydrolase activity was higher in the prepupa than in the larval stages. Profenofos inhibited pNAA hydrolase activity to a much greater extent than DEF. The enzyme activity was inhibited by DFB at relatively high concentrations. Determination of Michaelis-Menten kinetics with and without DFB revealed typical competitive reversible inhibition plots. The inhibition depended on the concentrations of enzyme, substrate, and inhibitor. Inhibition of pNAA hydrolysis occurred in the presence of DFB or its antibodies. Our findings indicate the possibility of using pNAA as a surrogate substrate for DFB hydrolase activity. The enzyme assay is accurate and easy to perform and may open up new avenues of research aimed at evaluating defense systems and resistance mechanisms to DFB and other benzoylphenyl ureas. © 1995 Academic Press, Inc.
Scientific Publication
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