The hemeâindependent manganeseâperoxidase activity depends on the presence of the Câterminal domain within the Streptomyces reticuli catalaseâperoxidase CpeB
2000
Zou, Peijian | Schrempf, Hildgund
Streptomyces reticuli produces a hemeâcontaining homodimeric enzyme (160âkDa), the catalaseâperoxidase CpeB, which is processed to the enzyme CpeC during prolonged growth. CpeC contains four subunits of 60âkDa each that do not include the Câterminal portion of the progenitor subunits. A genetically engineered cpeB gene encodes a truncated subunit lacking 195 of the Câterminal amino acids; four of these subunits assemble to form the enzyme CpeD. Heme binds most strongly in CpeB, least in CpeD. The catalaseâperoxidase CpeB and its apoâform (obtained after extraction of heme) catalyze the peroxidation of Mn(II) to Mn(III), independent of the presence or absence of the heme inhibitor KCN. CpeC and CpeD, in contrast, do not exhibit manganeseâperoxidase activity. The data show for the first time that a bacterial catalaseâperoxidase has a hemeâindependent manganeseâperoxidase activity, which depends on the presence of the Câterminal domain.
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