W. Henning et al., HIGH-YIELD PURIFICATION OF CYTOCHROME AA(3) AND CYTOCHROME CAA(3) OXIDASES FROM BACILLUS-SUBTILIS PLASMA-MEMBRANES, Biochemical journal, 309, 1995, pp. 279-283
When grown in aerated shaking culture, Bacillus subtilis expresses two
different haem A-containing terminal oxidases: cytochrome aa(3)-quino
l oxidase and cytochrome caa(3) oxidase. This paper describes a high-y
ield conventional procedure for purifying the two haem A-containing ox
idases from the same aerobic culture of Bacillus subtilis. Yields of c
lose to 40% of the total haem A are achieved and about 6 mg of each of
the purified oxidases is obtained from 4 litres of liquid culture. Bo
th of the purified enzymes have two subunits, with apparent molecular
masses of 71.6 kDa and 34.3 kDa for the cytochrome can, oxidase, and 6
7.6 kDa and 37.2 kDa for aa(3)-quinol oxidase. These features are in a
greement with the sequence data for the corresponding structural genes
in the aa(3) and caa(3) operons of B. subtilis. Some spectral and enz
ymic features of the two purified oxidases are reported that are consi
stent with the inclusion of both of these enzymes as members of the cy
tochrome oxidase superfamily.