TY - JOUR
T1 - Effect of iron concentration on the expression and activity of catalase-peroxidases in mycobacteria
AU - Yeruva, Veena C.
AU - Sundaram, C. A.S.Sivagami
AU - Sritharan, Manjula
PY - 2005/2
Y1 - 2005/2
N2 - Mycobacterial catalases are known to exist in different isoforms. We studied the influence of iron concentration on the expression and activity of the different isoforms in Mycobacterium bovis BCG, M. smegmatis, M. fortuitum, M. kansasii and M. vaccae by growing them under iron-sufficient (4 μg Fe/mL) and iron-deficient (0.02 μg Fe/ml) conditions. Upon iron deprivation, significant differences were observed in the catalase/peroxidase activities in both quantitative spectrophotometric assays and in the activity staining in native gels. Notable feature was that the peroxidase activity showed a significant decrease upon iron deprivation in all the mycobacteria, except M. vaccae. Peroxidase activity in all the mycobacteria, irrespective of the iron status was susceptible to heat inactivation. However, the isoforms of catalase showed differences in their heat stability, indicating possible structural differences in these proteins. For example, M. bovis BCG expressed a heat labile catalase under iron-sufficient conditions, while a heat stable catalase band of similar mobility was expressed under iron-deprivation conditions. The study clearly indicates that iron plays an important role in the regulation of expression of the different isoforms of the catalase-peroxidases.
AB - Mycobacterial catalases are known to exist in different isoforms. We studied the influence of iron concentration on the expression and activity of the different isoforms in Mycobacterium bovis BCG, M. smegmatis, M. fortuitum, M. kansasii and M. vaccae by growing them under iron-sufficient (4 μg Fe/mL) and iron-deficient (0.02 μg Fe/ml) conditions. Upon iron deprivation, significant differences were observed in the catalase/peroxidase activities in both quantitative spectrophotometric assays and in the activity staining in native gels. Notable feature was that the peroxidase activity showed a significant decrease upon iron deprivation in all the mycobacteria, except M. vaccae. Peroxidase activity in all the mycobacteria, irrespective of the iron status was susceptible to heat inactivation. However, the isoforms of catalase showed differences in their heat stability, indicating possible structural differences in these proteins. For example, M. bovis BCG expressed a heat labile catalase under iron-sufficient conditions, while a heat stable catalase band of similar mobility was expressed under iron-deprivation conditions. The study clearly indicates that iron plays an important role in the regulation of expression of the different isoforms of the catalase-peroxidases.
KW - Catalase-peroxidases
KW - Iron
KW - Mycobacteria
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M3 - Article
C2 - 23923578
AN - SCOPUS:28244476843
SN - 0301-1208
VL - 42
SP - 28
EP - 33
JO - Indian Journal of Biochemistry and Biophysics
JF - Indian Journal of Biochemistry and Biophysics
IS - 1
ER -