Spectroscopic characterization of the active (FeFeIII)-Fe-III and (FeFeII)-Fe-III forms of a purple acid phosphatase model system

Comba, Peter, Gahan, Lawrence R., Mereacre, Valeriu, Hanson, Graeme R., Powell, Annie K., Schenk, Gerhard and Zajaczkowski-Fischer, Marta (2012) Spectroscopic characterization of the active (FeFeIII)-Fe-III and (FeFeII)-Fe-III forms of a purple acid phosphatase model system. Inorganic Chemistry, 51 22: 12195-12209. doi:10.1021/ic301347t

Author Comba, Peter
Gahan, Lawrence R.
Mereacre, Valeriu
Hanson, Graeme R.
Powell, Annie K.
Schenk, Gerhard
Zajaczkowski-Fischer, Marta
Title Spectroscopic characterization of the active (FeFeIII)-Fe-III and (FeFeII)-Fe-III forms of a purple acid phosphatase model system
Journal name Inorganic Chemistry   Check publisher's open access policy
ISSN 0020-1669
Publication date 2012-11
Sub-type Article (original research)
DOI 10.1021/ic301347t
Volume 51
Issue 22
Start page 12195
End page 12209
Total pages 15
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2013
Language eng
Formatted abstract
Two new dinucleating ligands (H 3L 2 and HL 3), derivatives of a well-known dinucleating ligand (HL 1) with two bis-picolylamine sites connected to a bridging phenolate, with hydrogen-bonding donor groups at two of the pyridine moieties were designed and synthesized. Design of these ligands suggests that they will lead to dinuclear complexes with potential to stabilize phosphoester substrates as monodentate rather than bridging ligands. We report the diferric complexes [Fe III 2(H 2L 2)(OH)] 4+ and [Fe III 2(L 3)(OH)(OH 2) 2] 4+, which have been characterized by spectrophotometric titrations, UV-vis, IR, NMR, EPR, and Mössbauer spectroscopy. The phosphatase activity of the diferric systems, in addition to the partially reduced heterovalent [Fe IIIFe II(L 3)(OH)(OH 2) 2] 3+ complex, has been investigated, and the complexes are shown to catalytically hydrolyze the activated phosphodiester substrate BDNPP (bis-dinitrophenylphosphate) as well as the corresponding phosphomonoester substrate DNPP (dinitrophenylphosphate). The results indicate that indeed the secondary interactions lead to an increase of the phosphatase activity and to active phosphomonoesterase catalysts. Interestingly, the heterovalent form of the HL 3-based complex is more efficient than the diferric complex, and this is also discussed.
Keyword Dinucleating ligand
Phosphoester substrates
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
Centre for Advanced Imaging Publications
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