Studies on the adenosine triphosphate–phosphate exchange and the hydrolysis of adenosine triphosphate catalysed by a particulate fraction from the mosquito

Abstract

Adenosine triphosphatase and the enzyme system catalyzing the incorporation of P32 into adenosine triphosphate have been studied in respiratory particles prepared from the mosquito Aedes aegypti L. Addition of ethylenediaminetetra-acetic acid to the isolation medium and of ethylenediaminetetra-acetic acid and albumin either to the washing liquid or to the assay medium has been found obligatory for the exchange reaction. The effect of nucleotides, respiratory inhibitors and inhibitors of oxidative phosphorylation on the exchange reaction and on the adenosine triphosphate activity has been investigated. Quantitative differences exist between the response of insect and mammalian respiratory particles to 1, 1, 1-trichloro-2, 2-di-(p-chlorophenyl)-ethane (DDT). 0. 1 mM DDT inhibits the exchange reaction by more than 50% in insect sarcosomes whereas the inhibition in mammalian liver mitochondria is less than 10%.