In vitro effect of dimethoate on the activity of tryptophan pyrrolase in rat liver.
Total and holo-enzyme activities of tryptophan 2,3-dioxygenase were measured in vitro in the presence and absence of the organophosphorous insecticide, dimethoate. Addition of dimethoate to the reaction mixture decreased the activities of both total and holo-forms. Total and holo-enzyme activities were decreased by 34% and 26%, respectively, by 1 mM dimethoate. On the other hand, 5 mM dimethoate resulted in 56% and 34% inhibition to total and holo-enzyme activities, respectively. Lineweaver-Burk plot of the total-enzyme activity at different tryptophan concentration in the presence of 2 mM dimethoate gave uncompetitive type of inhibition.
Hassan
A A
AA
Applied Medical Chemistry Department, Alexandria university, Egypt.
el-Sewedy
S M
SM
Minatogawa
Y
Y
Kido
R
R
D000818:Animals; D004117:Dimethoate / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D014366:Tryptophan Oxygenase / Q000037:antagonists & inhibitors*
D014366:Tryptophan Oxygenase; D004117:Dimethoate