Arginase catalase activity

However, arginases also exhibit very weak catalase activity [111] (k0JKu = 11 M l sec-1 cf. catalases Table 3), not unexpectedly, considering their catalase-like active site. 

Not surprisingly, both manganese ions are necessary for the catalase activity of arginase, as confirmed by metal replacement experiments in a mutant arginase. Indeed, whereas the hydrolytic reaction was restored upon binding one Cd2+ ion to form a heteronuclear MnCd enzyme, catalase activity was not [111]. 

V. MANGANESE CATALASE AND CATALASE-TYPE ACTIVITY OF ARGINASE... 

B contains significant amounts of manganese. The EPR data [171] suggest the presence in protein B of a spin-coupled dinuclear Mn11 cluster, perhaps of the type found in catalases and arginases. No additional information about the metal active site is currently available. 

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