Properties of the ATP phosphohydrolase of the facultative thermophile Bacillus coagulans

Abstract

The thermostability of the ATP phosphohydrolase of the facultative thermophile Bacillus coagulans has been investigated. Fractionation of disintegrated cell suspensions by differential centrifugation revealed a similar distribution of enzyme activity irrespective of growth temperature. Most of the activity was located in the membrane fraction. Thermostability of solubilized (BF1) preparation from cells grown at 37°C or 55°C was similar, but membrane‐bound BF0BF1 from 37°C‐grown cells was inactivated at lower temperatures than that from 55°C‐grown cells. Inhibition of the membrane‐bound (BF0BF1)ATPase by 4‐chloro‐7‐nitro‐benzofuran (NbfCl) and quercetin, which both act on the BF1 portion of the enzyme, was different from that seen with the soluble (BF1) enzyme. The results show that some modification of BF1 must occur when the enzyme is membrane‐bound.

Thermotolerance of the Respiratory Chain of Bacillus Coagulans

“…In this paper we examine the thermotolerance of the respiratory chain of B. coagulans in the light of previous work which showed the presence of a thermostable ATPase and oxygendependent modulation of respiratory chain composition brought about by growth at different temperatures (Edwards & Jones, 1983;Jones et al, 1984;Ball et al, 1985;Ball & Edwards, 1986).…”