TERMINAL OXIDASES OF THE BB-TYPES AND CAA(3)-TYPES IN BACILLUS SP FTU

We previously identified two oxidases in the membranes of bacterium Ba cillus sp. FTU. One of them slowly (caa(3)) and the other rapidly (be) recombines with carbon monoxide (CO) after laser flash photolysis, in this respect resembling the Escherichia coli bo- and bd-type oxidases , respectively. In the present study we found three copper atoms in th e slowly CO-recombining oxidase from Bacillus sp. FTU. In the other ox idase, the copper content is very low and clearly substoichiometric. R eversed-phase chromatography revealed the presence of haems A and C in the Bacillus sp. FTU copper-containing oxidase and haems B and C in t he non-copper-containing one. We thus suggest that the Bacillus sp. FT U oxidase rapidly reacting with CO previously attributed to bo-type by analogy in redox spectrum with the E. coli enzyme be redefined as bb- type oxidase. (C) 1995 Academic Press, Inc.