Kinetic and structural studies of N-acetyl-microperoxidase-5 and - microperoxidase-8

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Abstract

The smallest microperoxidase-5 (MP-5) was obtained from proteolytic digestion of cytochrome c. The heme c group of MP-5 links the pentapeptide Cys14-Ala-Gln-Cys-His18 through two thioether bonds. MP-5 exists in the ferric resting state with His18 as the proximal ligand and with water in the sixth coordination site. From the optical spectral studies on the aggregation of MP-5 and Nα-acetyl-microperoxidase-5 (Ac-MP-5), we observed that MP-5 and Ac-MP-5 exhibit different aggregation states. At concentrations greater than 10 μM, MP-5 exists as a mixture of monomers and dimers. The intermolecular coordination of MP-5 is abolished by acetylation, and Ac-MP-5 clearly exists as a high-spin, six-coordinate ferriheme. However, the porphyrin-porphyrin interaction between Ac-MP-5 cannot be eliminated. The substrate, o-methoxyphenol, was oxidized by hydrogen peroxide using Ac-MP-5 and Ac-MP-8 as catalysts. Comparisons of the peroxidase activities of Ac-MP- 5, MP-8, and Ac-MP-8 suggest that microperoxidases (MPs) retain the same peroxidase activity as long as His-18 coordinates to ferriheme. Circular dichroism (CD) analyses of Ac-MP-5 and Ac-MP-8 show β-turns in the peptide region, indicating rigidity. Based on CD analyses of MPs, we have built a molecular model for Ac-MP-5 containing a β-turn in the peptide region.

Original languageEnglish
Pages (from-to)93-97
Number of pages5
JournalJournal of Inorganic Biochemistry
Volume75
Issue number2
DOIs
Publication statusPublished - 1999 Jun 15

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Kinetics
Porphyrins
Circular Dichroism
microperoxidase
Peroxidase
Agglomeration
Acetylation
Peptides
Molecular Models
Sulfides
Cytochromes c
Heme
Rigidity
Dimers
Hydrogen Peroxide
Digestion
Monomers
Ligands
Catalysts
Water

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Inorganic Chemistry

Cite this

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title = "Kinetic and structural studies of N-acetyl-microperoxidase-5 and - microperoxidase-8",
abstract = "The smallest microperoxidase-5 (MP-5) was obtained from proteolytic digestion of cytochrome c. The heme c group of MP-5 links the pentapeptide Cys14-Ala-Gln-Cys-His18 through two thioether bonds. MP-5 exists in the ferric resting state with His18 as the proximal ligand and with water in the sixth coordination site. From the optical spectral studies on the aggregation of MP-5 and Nα-acetyl-microperoxidase-5 (Ac-MP-5), we observed that MP-5 and Ac-MP-5 exhibit different aggregation states. At concentrations greater than 10 μM, MP-5 exists as a mixture of monomers and dimers. The intermolecular coordination of MP-5 is abolished by acetylation, and Ac-MP-5 clearly exists as a high-spin, six-coordinate ferriheme. However, the porphyrin-porphyrin interaction between Ac-MP-5 cannot be eliminated. The substrate, o-methoxyphenol, was oxidized by hydrogen peroxide using Ac-MP-5 and Ac-MP-8 as catalysts. Comparisons of the peroxidase activities of Ac-MP- 5, MP-8, and Ac-MP-8 suggest that microperoxidases (MPs) retain the same peroxidase activity as long as His-18 coordinates to ferriheme. Circular dichroism (CD) analyses of Ac-MP-5 and Ac-MP-8 show β-turns in the peptide region, indicating rigidity. Based on CD analyses of MPs, we have built a molecular model for Ac-MP-5 containing a β-turn in the peptide region.",
author = "Woei-Jer Chuang and Chang, {Yuh Dar} and Wen-Yih Jeng",
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Kinetic and structural studies of N-acetyl-microperoxidase-5 and - microperoxidase-8. / Chuang, Woei-Jer; Chang, Yuh Dar; Jeng, Wen-Yih.

In: Journal of Inorganic Biochemistry, Vol. 75, No. 2, 15.06.1999, p. 93-97.

Research output: Contribution to journalArticle

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T1 - Kinetic and structural studies of N-acetyl-microperoxidase-5 and - microperoxidase-8

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AU - Chang, Yuh Dar

AU - Jeng, Wen-Yih

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N2 - The smallest microperoxidase-5 (MP-5) was obtained from proteolytic digestion of cytochrome c. The heme c group of MP-5 links the pentapeptide Cys14-Ala-Gln-Cys-His18 through two thioether bonds. MP-5 exists in the ferric resting state with His18 as the proximal ligand and with water in the sixth coordination site. From the optical spectral studies on the aggregation of MP-5 and Nα-acetyl-microperoxidase-5 (Ac-MP-5), we observed that MP-5 and Ac-MP-5 exhibit different aggregation states. At concentrations greater than 10 μM, MP-5 exists as a mixture of monomers and dimers. The intermolecular coordination of MP-5 is abolished by acetylation, and Ac-MP-5 clearly exists as a high-spin, six-coordinate ferriheme. However, the porphyrin-porphyrin interaction between Ac-MP-5 cannot be eliminated. The substrate, o-methoxyphenol, was oxidized by hydrogen peroxide using Ac-MP-5 and Ac-MP-8 as catalysts. Comparisons of the peroxidase activities of Ac-MP- 5, MP-8, and Ac-MP-8 suggest that microperoxidases (MPs) retain the same peroxidase activity as long as His-18 coordinates to ferriheme. Circular dichroism (CD) analyses of Ac-MP-5 and Ac-MP-8 show β-turns in the peptide region, indicating rigidity. Based on CD analyses of MPs, we have built a molecular model for Ac-MP-5 containing a β-turn in the peptide region.

AB - The smallest microperoxidase-5 (MP-5) was obtained from proteolytic digestion of cytochrome c. The heme c group of MP-5 links the pentapeptide Cys14-Ala-Gln-Cys-His18 through two thioether bonds. MP-5 exists in the ferric resting state with His18 as the proximal ligand and with water in the sixth coordination site. From the optical spectral studies on the aggregation of MP-5 and Nα-acetyl-microperoxidase-5 (Ac-MP-5), we observed that MP-5 and Ac-MP-5 exhibit different aggregation states. At concentrations greater than 10 μM, MP-5 exists as a mixture of monomers and dimers. The intermolecular coordination of MP-5 is abolished by acetylation, and Ac-MP-5 clearly exists as a high-spin, six-coordinate ferriheme. However, the porphyrin-porphyrin interaction between Ac-MP-5 cannot be eliminated. The substrate, o-methoxyphenol, was oxidized by hydrogen peroxide using Ac-MP-5 and Ac-MP-8 as catalysts. Comparisons of the peroxidase activities of Ac-MP- 5, MP-8, and Ac-MP-8 suggest that microperoxidases (MPs) retain the same peroxidase activity as long as His-18 coordinates to ferriheme. Circular dichroism (CD) analyses of Ac-MP-5 and Ac-MP-8 show β-turns in the peptide region, indicating rigidity. Based on CD analyses of MPs, we have built a molecular model for Ac-MP-5 containing a β-turn in the peptide region.

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