- 【Updated on May 12, 2025】 Integration of CiNii Dissertations and CiNii Books into CiNii Research
- Trial version of CiNii Research Knowledge Graph Search feature is available on CiNii Labs
- 【Updated on June 30, 2025】Suspension and deletion of data provided by Nikkei BP
- Regarding the recording of “Research Data” and “Evidence Data”
Mechanism of Superoxide Dismutase-Like Activity of Fe(II) and Fe(III) Complexes of Tetrakis-N,N,N',N'(2-pyridylmethyl)ethylenediamine.
Bibliographic Information
- Other Title
-
- Mechanism of Superoxide Dismutase-Like Activity of Fe(II)and Fe(III) Complexes of Tetrakis-N,N,N′,N′(2-pyridylmethyl)ethylenediamine
Search this article
Description
The superoxide dismutase (SOD) activity of iron(II) tetrakis-N, N, N', N' (2-pyridylmethyl)ethylenediamine complex (Fe-TPEN) was reexamined using a pulse radiolysis mehtod. In our previous study (J. Biol. Chem., 264, 9243-9249 (1989)), we reportd that this complex has a potent SOD activity in a cyt. c (cytochrome c)-based system (IC50=0.8 μM) and protects E. coli cells against paraquat toxicity . The present pulse radiolysis experiment revealed that Fe(II)TPEN reacts stoichiometrically with superoxide to form Fe(III)TPEN with a second-order rate constant of 3.9×106M-1s-1 at pH 7.1, but superoxide did not reduce Fe(III)TPEN to Fe(II)TPEN. The reaction of Fe(III)TPEN and superoxide was biphasic. In the fast reaction, an adduct (Fe(III)TPEN-superoxide complex) was formed at the second-order rate constant of 8.5×105M-1S-1 at pH 7.4. In the slow one, the adduct reacted with another moleculre of the adduct, regenerating Fe(III)TPEN. In the cyt. c method with catalase, this Fe(III)TPEN-superoxide complex showed cyt.c oxidation activity, which had led to overstimation of its SOD activity. Based on the titration data, the main species of complex in aqueous media at neutral pH was indicated to be Fe(III)TPEN(OH-). A spectral chagne after the reduction with hydrated electron indicates that the OH- ion coordinates directly to Fe(III) by displacing one of the pyridine rings. The X-ray analysis of [Fe(II)TPEN]SO4 supported this structure. From the above results we propose a novel reaction mechanism of FeTPEN and superoxide which resembles a proton catalyzed dismuting process, involving Fe(III)TPEN-superoxide complex.
Journal
-
- Chemical and Pharmaceutical Bulletin
-
Chemical and Pharmaceutical Bulletin 48 (2), 223-230, 2000
The Pharmaceutical Society of Japan
- Tweet
Keywords
Details 詳細情報について
-
- CRID
- 1390001204162579456
-
- NII Article ID
- 130003948053
- 110003635433
-
- NII Book ID
- AA00602100
-
- ISSN
- 13475223
- 00092363
-
- NDL BIB ID
- 4978560
-
- PubMed
- 10705509
-
- Text Lang
- en
-
- Article Type
- journal article
-
- Data Source
-
- JaLC
- NDL Search
- Crossref
- PubMed
- CiNii Articles
- OpenAIRE
-
- Abstract License Flag
- Disallowed