Characterization of a bifunctional catalase-peroxidase of Burkholderia cenocepacia.
Isolates of Burkholderia cenocepacia express a putative haem-binding protein (molecular mass 97 kDa) that displays intrinsic peroxidase activity. Its role has been re-evaluated, and we now show that it is a bifunctional catalase-peroxidase, with activity against tetramethylbenzidine (TMB), o-dianisidine, pyrogallol, and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic) acid (ABTS). Both peroxidase and catalase activities are optimal at pH 5.5-6.0. The gene encoding this enzyme was cloned and expressed in Escherichia coli. We have named it katG because of its similarity to other katGs, including that from Burkholderia pseudomallei. It is substantially similar to a previously described catalase-peroxidase of B. cenocepacia (katA). MS analysis indicated that the initial katG translation product may be post-translationally modified in B. cenocepacia to give rise to the mature 97-kDa catalase-peroxidase.
Charalabous
Panagoula
P
Microbiology, The University of Liverpool, Liverpool, UK.
Risk
Janet M
JM
Jenkins
Rosalind
R
Birss
Andrew J
AJ
Hart
C Anthony
CA
Smalley
John W
JW
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D019117:Burkholderia / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D010544:Peroxidases; C081610:catalase-peroxidase, bacteria