Model of the extradiol-cleaving manganese(II) dioxygenase penicillamine-manganese(II) complex.

The structure of the green penicillamine(Pen)-Mn(II) complex prepared under air was determined from its electronic spectra, molar ratio, ESR spectra and oxygen consumptions at various pH values and by potentiometric titration. Pen bound with Mn(II) in a molar ratio of approximately 1:1 forming coordination bonds with a thiolate and an amino group, and the complex consumed about 1 mol of oxygen at pH 9-10. Oxygen binding to this complex was found to be reversible at room temperature. The oxygen adduct complex catalysed oxidative extradiol-cleavage of catechol at pH 7.0-7.5. The Pen-Mn(II)-02 complex seems to be a simple model of extradiol-cleaving manganese(II) dioxygenase, which was recently found in Bacillus brevis.