Reduction of ferricytochrome c by tyrosyltyrosylphenylalanine

S. Hirota, H. Okumura, Shigeki Kuroiwa, N. Funasaki, Y. Watanabe

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Cytochrome c (cyt c) was reduced by a tyrosine-containing peptide, tyrosyltyrosylphenylalanine (TyrTyrPhe), at pH 6.0-8.0, while tyrosinol or tyrosyltyrosine (TyrTyr) could not reduce cyt c effectively under the same condition. Cyt c was reduced at high peptide concentration, whereas the reaction did not occur effectively at low concentration. The reaction rate varied with time owing to a decrease in the TyrTyrPhe concentration and the production of tyrosine derivatives during the reaction. The initial rate constants were 2.4×10-4 and 8.1×10-4 s-1 at pH 7.0 and 8.0, respectively, for the reaction with 1.0 mM TyrTyrPhe in 10 mM phosphate buffer at 15°C. The reciprocal initial rate constant (1/k int) increased linearly against the reciprocal peptide concentration and against the linear proton concentration, whereas logk int decreased linearly against the root of the ionic strength. These results show that deprotonated (TyrTyrPhe)-, presumably deprotonated at a tyrosine site, reduces cyt c by formation of an electrostatic complex. No significant difference in the reaction rate was observed between the reaction under nitrogen and oxygen atmospheres. From the matrix-assisted laser desorption ionization time-of-flight mass spectra of the reaction products, formation of a quinone and other tyrosine derivatives of the peptide was supported. These products should have been produced from a tyrosyl radical. We interpret the results that a cyt cox/(TyrTyrPhe)- ⇌ cyt cred/(TyrTyrPhe) equilibrium is formed, which is usually shifted to the left. This equilibrium may shift to the right by reaction of the produced tyrosyl radical with the tyrosine sites of unreacted TyrTyrPhe peptides.

Original languageEnglish
Pages (from-to)355-363
Number of pages9
JournalJournal of Biological Inorganic Chemistry
Volume10
Issue number4
DOIs
Publication statusPublished - 2005 Jun
Externally publishedYes

Fingerprint

Cytochromes c
Tyrosine
Peptides
tyrosyltyrosine
Reaction rates
Rate constants
Derivatives
Ionic strength
Static Electricity
Atmosphere
Reaction products
Osmolar Concentration
Ionization
Protons
Electrostatics
Desorption
Buffers
Lasers
Nitrogen
Phosphates

Keywords

  • Cytochrome c
  • Electron transfer
  • Heme reduction
  • Tyrosine-containing peptide
  • Tyrosyl radical

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry

Cite this

Reduction of ferricytochrome c by tyrosyltyrosylphenylalanine. / Hirota, S.; Okumura, H.; Kuroiwa, Shigeki; Funasaki, N.; Watanabe, Y.

In: Journal of Biological Inorganic Chemistry, Vol. 10, No. 4, 06.2005, p. 355-363.

Research output: Contribution to journalArticle

Hirota, S. ; Okumura, H. ; Kuroiwa, Shigeki ; Funasaki, N. ; Watanabe, Y. / Reduction of ferricytochrome c by tyrosyltyrosylphenylalanine. In: Journal of Biological Inorganic Chemistry. 2005 ; Vol. 10, No. 4. pp. 355-363.
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abstract = "Cytochrome c (cyt c) was reduced by a tyrosine-containing peptide, tyrosyltyrosylphenylalanine (TyrTyrPhe), at pH 6.0-8.0, while tyrosinol or tyrosyltyrosine (TyrTyr) could not reduce cyt c effectively under the same condition. Cyt c was reduced at high peptide concentration, whereas the reaction did not occur effectively at low concentration. The reaction rate varied with time owing to a decrease in the TyrTyrPhe concentration and the production of tyrosine derivatives during the reaction. The initial rate constants were 2.4×10-4 and 8.1×10-4 s-1 at pH 7.0 and 8.0, respectively, for the reaction with 1.0 mM TyrTyrPhe in 10 mM phosphate buffer at 15°C. The reciprocal initial rate constant (1/k int) increased linearly against the reciprocal peptide concentration and against the linear proton concentration, whereas logk int decreased linearly against the root of the ionic strength. These results show that deprotonated (TyrTyrPhe)-, presumably deprotonated at a tyrosine site, reduces cyt c by formation of an electrostatic complex. No significant difference in the reaction rate was observed between the reaction under nitrogen and oxygen atmospheres. From the matrix-assisted laser desorption ionization time-of-flight mass spectra of the reaction products, formation of a quinone and other tyrosine derivatives of the peptide was supported. These products should have been produced from a tyrosyl radical. We interpret the results that a cyt cox/(TyrTyrPhe)- ⇌ cyt cred/(TyrTyrPhe) • equilibrium is formed, which is usually shifted to the left. This equilibrium may shift to the right by reaction of the produced tyrosyl radical with the tyrosine sites of unreacted TyrTyrPhe peptides.",
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T1 - Reduction of ferricytochrome c by tyrosyltyrosylphenylalanine

AU - Hirota, S.

AU - Okumura, H.

AU - Kuroiwa, Shigeki

AU - Funasaki, N.

AU - Watanabe, Y.

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N2 - Cytochrome c (cyt c) was reduced by a tyrosine-containing peptide, tyrosyltyrosylphenylalanine (TyrTyrPhe), at pH 6.0-8.0, while tyrosinol or tyrosyltyrosine (TyrTyr) could not reduce cyt c effectively under the same condition. Cyt c was reduced at high peptide concentration, whereas the reaction did not occur effectively at low concentration. The reaction rate varied with time owing to a decrease in the TyrTyrPhe concentration and the production of tyrosine derivatives during the reaction. The initial rate constants were 2.4×10-4 and 8.1×10-4 s-1 at pH 7.0 and 8.0, respectively, for the reaction with 1.0 mM TyrTyrPhe in 10 mM phosphate buffer at 15°C. The reciprocal initial rate constant (1/k int) increased linearly against the reciprocal peptide concentration and against the linear proton concentration, whereas logk int decreased linearly against the root of the ionic strength. These results show that deprotonated (TyrTyrPhe)-, presumably deprotonated at a tyrosine site, reduces cyt c by formation of an electrostatic complex. No significant difference in the reaction rate was observed between the reaction under nitrogen and oxygen atmospheres. From the matrix-assisted laser desorption ionization time-of-flight mass spectra of the reaction products, formation of a quinone and other tyrosine derivatives of the peptide was supported. These products should have been produced from a tyrosyl radical. We interpret the results that a cyt cox/(TyrTyrPhe)- ⇌ cyt cred/(TyrTyrPhe) • equilibrium is formed, which is usually shifted to the left. This equilibrium may shift to the right by reaction of the produced tyrosyl radical with the tyrosine sites of unreacted TyrTyrPhe peptides.

AB - Cytochrome c (cyt c) was reduced by a tyrosine-containing peptide, tyrosyltyrosylphenylalanine (TyrTyrPhe), at pH 6.0-8.0, while tyrosinol or tyrosyltyrosine (TyrTyr) could not reduce cyt c effectively under the same condition. Cyt c was reduced at high peptide concentration, whereas the reaction did not occur effectively at low concentration. The reaction rate varied with time owing to a decrease in the TyrTyrPhe concentration and the production of tyrosine derivatives during the reaction. The initial rate constants were 2.4×10-4 and 8.1×10-4 s-1 at pH 7.0 and 8.0, respectively, for the reaction with 1.0 mM TyrTyrPhe in 10 mM phosphate buffer at 15°C. The reciprocal initial rate constant (1/k int) increased linearly against the reciprocal peptide concentration and against the linear proton concentration, whereas logk int decreased linearly against the root of the ionic strength. These results show that deprotonated (TyrTyrPhe)-, presumably deprotonated at a tyrosine site, reduces cyt c by formation of an electrostatic complex. No significant difference in the reaction rate was observed between the reaction under nitrogen and oxygen atmospheres. From the matrix-assisted laser desorption ionization time-of-flight mass spectra of the reaction products, formation of a quinone and other tyrosine derivatives of the peptide was supported. These products should have been produced from a tyrosyl radical. We interpret the results that a cyt cox/(TyrTyrPhe)- ⇌ cyt cred/(TyrTyrPhe) • equilibrium is formed, which is usually shifted to the left. This equilibrium may shift to the right by reaction of the produced tyrosyl radical with the tyrosine sites of unreacted TyrTyrPhe peptides.

KW - Cytochrome c

KW - Electron transfer

KW - Heme reduction

KW - Tyrosine-containing peptide

KW - Tyrosyl radical

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