Glutathione-mediated mineralization of C-14-labeled 2-amino-4,6-dinitrotoluene by manganese-dependent peroxidase H5 from the white-rot fungus Phanerochaete chrysosporium
B. Van Aken et al., Glutathione-mediated mineralization of C-14-labeled 2-amino-4,6-dinitrotoluene by manganese-dependent peroxidase H5 from the white-rot fungus Phanerochaete chrysosporium, APPL MICR B, 54(5), 2000, pp. 659-664
Manganese-dependent peroxidase (MnP) H5 from the white-rot fungus Phaneroch
aete chrysosporium, in the presence of either Mn(II)(10 mM) or GSH (10 mM),
was able to mineralize C-14-U-ring-labeled 2-amino-4,6-dinitrotoluene (2-A
-4,6-DNT) up to 29% in 12 days. When both Mn(II) and GSH were present, the
mineralization extent reached 82%. On the other hand, no significant minera
lization was observed in the absence of both Mn(II) and GSH, suggesting the
requirement of a mediator [either Mn(II) or GSH] for the degradation of 2-
A-4,6-DNT by MnP. Using electron spin resonance (ESR) techniques, it was fo
und that the glutathionyl free radical (GS(.)) was produced through the oxi
dation of GSH by MnP in the presence as well as in the absence of Mn(II). G
S . was also generated through the direct oxidation of GSH by Mn(III). Our
results strongly suggest the involvement of GS . in the GSH-mediated minera
lization of 2-A-4,6-DNT by MnP.