60 research outputs found
A New Heterobinuclear FeIIICuII Complex with a Single Terminal FeIII–O(phenolate) Bond. Relevance to Purple Acid Phosphatases and Nucleases
A novel heterobinuclear mixed valence complex [Fe^IIICu^II(BPBPMP)(OAc)_2]ClO_4, 1, with the unsymmetrical N_5O_2 donor ligand 2-bis[{(2-pyridylmethyl)aminomethyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)} aminomethyl]-4-methylphenol (H_2BPBPMP) has been synthesized and characterized. A combination of data from mass spectrometry, potentiometric titrations, X-ray absorption and electron paramagnetic resonance spectroscopy, as well as kinetics measurements indicates that in ethanol/water solutions an [Fe^III-(nu)OH-Cu^IIOH_2]+ species is generated which is the likely catalyst for 2,4-bis(dinitrophenyl)phosphate and DNA hydrolysis. Insofar as the data are consistent with the presence of an Fe_III-bound hydroxide acting as a nucleophile during catalysis, 1 presents a suitable mimic for the hydrolytic enzyme purple acid phosphatase. Notably, 1 is significantly more reactive than its isostructural homologues with different metal composition (Fe^IIIM^II, where M^II is Zn^II, Mn^II, Ni^II,or Fe^II). Of particular interest is the observation that cleavage of double-stranded plasmid DNA occurs even at very low concentrations of 1 (2.5 nuM), under physiological conditions (optimum pH of 7.0), with a rate enhancement of 2.7 x 10^7 over the uncatalyzed reaction. Thus, 1 is one of the most effective model complexes to date, mimicking the function of nucleases
A Radical on the Met-Tyr-Trp Modification Required for Catalase Activity in Catalase-Peroxidase Is Established by Isotopic Labeling and Site-Directed Mutagenesis
Spectroscopic Evidence for a Heme−Superoxide/Cu(I) Intermediate in a Functional Model of Cytochrome c
Synthesis, Characterization, and Laser Flash Photolysis Reactivity of a Carbonmonoxy Heme Complex
Two [Fe(IV)dO Trp] Intermediates in M. tuberculosis Catalase-Peroxidase Discriminated by Multifrequency (9-285 GHz) EPR Spectroscopy: Reactivity toward Isoniazid
Autocatalytic Formation of a Covalent Link between Tryptophan 41 and the Heme in Ascorbate Peroxidase
Synthesis and Spectroscopy of mu-Oxo (O2-) Bridged Heme/Non-heme Diiron Complexes: Models for the Active Site of Nitric Oxide Reductase
Synthesis and characterization of porphyrin-trisbenzimidazole dinucleating ligand and its heterodinuclear complex as CcO active site model
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