| Autor: |
Chiang R, Makino R, Spomer WE, Hager LP |
| Jazyk: |
angličtina |
| Zdroj: |
Biochemistry [Biochemistry] 1975 Sep 23; Vol. 14 (19), pp. 4166-71. |
| DOI: |
10.1021/bi00690a003 |
| Abstrakt: |
The oxidation state of the two half-cystine residues in the native ferric form of chloroperoxidase and in the reduced ferrous chloroperoxidase has been examined in order to evaluate the role of sulfhydryl groups as determinants of P-450 type spectra. Mössbauer and optical spectroscopy studies indicate that the ferrous forms of P-450cam and chloroperoxidase have very similar or identical heme environments. Model studies have suggested that sulfhydryl groups may function as axial ligands for developing P-450 character. However, chemical studies involving both sulfhydryl reagents and amperometric titrations show that neither the ferric nor the chemically produced ferrous forms of chloroperoxidase contain a sulfhydryl group. These results rule out the hypothesis that sulfhydryl groups are unique components for P-450 absorption characteristics. The optical and electron paramagnetic resonance (EPR) spectra of the nitric oxide complex of chloroperoxidase have been obtained and compared to those of myoglobin, hemoglobin, and cytochrome c and horseradish peroxidase. The EPR spectrum of the NO-ferrous chloroperoxidase complex, which is similar to that of cytochrome P-450cam, does not show the extra nitrogen hyperfine structure which appears to be characteristic of those hemoproteins which have a nitrogen atom as an axial heme ligand. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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