Hydrogen peroxide inactivate all peroxidases after
several cycles of catalysis as a consequence of the competition
between productive and unproductive electron
sources (including enzyme components) in a process
described as a suicide inactivation (Valderrama et al.,
2002). Different attempts aimed to improve hydrogen
peroxide stability of ligninolytic peroxidases have been
performed, mainly removing easily oxidizable and conformationally
unstable amino acid residues located at
the peroxide-binding side of haem with very promising
results (Miyazaki and Takahashi, 2001; Miyazaki-
Imamura et al., 2003). Recently, a novel peroxidase from
Raphanus sativus has been identified and characterized
as the only known case of a haemperoxidase intrinsically
resistant to hydrogen peroxide (Gil-Rodríguez et al.,
2008). In-depth analysis of its structure will give the first
structural evidences of peroxide stability to be used to
increase the peroxide stability of ligninolytic and other
peroxidases.