Ullrich 2023 MiPschool Obergurgl
Link: MiPschool Obergurgl 2023
Ullrich Volker (2023)
Event: MiPschool Obergurgl 2023
Authors: Ullrich Volker, Heidler Juliana, Schildknecht S, Daiber Andreas, Frensch M, Wittig Ilka, Bruene B
Introduction: Micelles containing cardiolipin (CL) and phosphatidylcholine in presence of cytochrome c (Cytc) and H2O2 were reported to catalyze peroxidationes of typical peroxidase substrates but also of CL itself (Kagan et. al, Biochem. 45,4998, 2006). This can be explained by complex formation of CL with Cytc under removal of the Met80 sixth ligand of the heme.
Methods: O2 consumption was measured polarographically (Orobos Instruments) and diene formation spectrally at 237 nm.
Results and Discussion: Cytc addition to CL micelles caused a burst of O2 uuptake that could be repeated until CL or O2 were depleted. About 4.5 mol of O2/mol CL were taken up forming products with mainly 2,4,6 or 8 additional O-atoms. Diene formation initially followed the same kinetics but stopped or was reversed before O2 uptake was completed. In presence of 2 M KCl Cytc acted catalytically with slower kinetics in three phases and showed oxidative modifications of the protein. The required peroxide tone originated from autoxidized CL and was upregulated during progress of the reaction. Significance for the process of opening of the permeability pore is suggested.
• Keywords: cardiolipin, cytochrome c, oxygen uptake, diene formation
- Ullrich Volker1, Heidler J2, Schildknecht S1, Daiber A3, Frensch M1, Wittig I2, Brüne B2
- Dept. Biol. Univ. of Konstanz, Germany
- Med. Fac. Dept. Biochem. II, Frankfurt, Germany
- Univ. Med. Center Dept. Cardiol. Univ. Mainz