Purification and characterization of two soluble cytochromes from the alkalophile Bacillus firmus RAB.
A soluble cytochrome c and soluble cytochrome b were purified from the alkalophilic Bacillus firmus RAB. The cytochrome c, with an alpha band at 552 nm, had an apparent molecular weight of 16,500 and was acidic, with a pI of 3.4. At both pH 7.0 and 8.3, the midpoint potential of c-552 was +66 mV. Above pH 8.3, the cytochrome exhibited a pH-dependent decrease in midpoint potential. This property, among others, distinguished the cytochrome c-552 from other membrane-associated c-type cytochromes. The soluble cytochrome b, with an alpha band maximum at 558 nm, had a molecular weight of approx. 15,500 and was also an acidic protein, with a pI of 3.07. It exhibited a pH-independent midpoint potential of +28 mV.
Davidson
M W
MW
Department of Biochemistry, Mount Sinai School of Medicine, City University of New York, NY 10029.
Gray
K A
KA
Knaff
D B
DB
Krulwich
T A
TA
D000596:Amino Acids / Q000032:analysis; D001407:Bacillus / Q000032:analysis*; D002462:Cell Membrane / Q000378:metabolism; D002850:Chromatography, Gel; D003573:Cytochrome b Group / Q000302:isolation & purification*; D003574:Cytochrome c Group / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008970:Molecular Weight; D010084:Oxidation-Reduction; D013053:Spectrophotometry
D000596:Amino Acids; D003573:Cytochrome b Group; D003574:Cytochrome c Group