Urethane as an inhibitor of the firefly light reaction.
A study has been made to test the hypothesis that general anesthetics such as urethane are able to inhibit light from a firefly reaction mixture. Urethane was found to reduce light emission in a dose-dependent manner, the minimal effective concentration being about 20 mM. Dixon plots gave a Ki value in the range of 175 to 215 mM. Lineweaver-Burk plots showed that urethane increases the apparent Km for ATP and reduces Vmax for the reaction. This is taken to mean that urethane acts as both a competitive and non-competitive inhibitor of the firefly light reaction (mixed-type inhibition).
Nehls
S M
SM
Department of Physiology, University of Wisconsin, Madison 53706.
Bittar
E E
EE
D000818:Animals; D001517:Coleoptera / Q000502:physiology*; D049454:Firefly Luciferin / Q000037:antagonists & inhibitors; D008156:Luciferases / Q000037:antagonists & inhibitors; D008163:Luminescent Measurements; D014520:Urethane / Q000494:pharmacology*
D014520:Urethane; D049454:Firefly Luciferin; D008156:Luciferases