Search

The biochemical and structural characterization of proteolyzed HPII, confirming that the large subunit HPII that can be truncated to a core structure that is similar in many respects to the small subunit clade Mn-containing and 78-84 kDa catalases is reported. It is found that the truncated variant exhibits a 1.8 times faster turnover rate and enhanced sensitivity to high concentrations of H(sub 2)O(sub 2) consistent with easier access of the substrate to the active site.

Results reveal that treatment of hydroperoxidase II with proteases under limited digestion conditions cleave 72-74 residues from the N-terminus of each sububit of the homotetrmer enzyme with 80% of the wild-type activity. Longer treatment of the enzyme with proteinase K removes the C-terminus but yet retains the tetrameric structure with 80% of the wild-type activity.