Pseudocatalase Lactobacillus plantarum

The bacterium Lactobacillus plantarum and its closest allies are unusual in that they are aerobic organisms but do not produce a superoxide dismutase. This bacterium instead accumulates Mn(II) to an intramolecular level on the order of 25 mM (150-152). In vitro studies indicated that Mn(II) formed a complex with lactate which possessed significant superoxide activity (153). These bacteria are additionally unable to produce heme and, consequently, when grown in the absence of heme, produce a hemeless catalase, or pseudocatalase (154-158). Unlike heme-containing catalases, the enzyme is not inhibited by cyanide or azide, and the addition of either Mn or Fe into the growth medium increased the amount of the pseudocatalase present. However, neither of the metals could be detected in partially purified enzyme assays (157). 

The catalase (or pseudocatalase) from Lactobacillus plantarum is also believed to contain a dimanganese(III) site in the oxidized form. It can be reduced to dimanganese(II) or superoxidized to a Mn Mn " state. The last complex shows a 16-line EPR spectrum (189). The visible spectrum of the dimanganese(III) form shows a strong absorption at... 

Kono Y, Eridovich I. 1983. Isolation and characterization of the pseudocatalase of Lactobacillus plantarum A new manganese-containing enzyme. J Biol Chem 258 6015-6019. 

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