Ullrich 2023 MiPschool Obergurgl

Ullrich Volker (2023) Cytochrome c as a Cardiolipin Dioxygenase. MiPschool Obergurgl 2023.

Link: MiPschool Obergurgl 2023

Ullrich Volker (2023)

Event: MiPschool Obergurgl 2023

Ullrich Volker 1, Heidler J 2, Schildknecht S 1, Daiber A3 Frensch M 1 ,Wittig I 2, Brüne B 2

1 Dept. Biol. Univ. of Konstanz 2 Med. Fac. Dept. Biochem. II, Frankfurt 3 Univ. Med. Center Dept. Cardiol. Univ. Mainz

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 is explained by complex formation of CL with Cytc under removal of the Met80 sixth ligand of the heme. Methods : O2 consumption was measured polographically (Orobos Instruments) and diene formation spectrally at 237 nm. Results and Discussion: Cytc addition to CL micelles caused a burst of O2 uptake 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 being 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 in opening of the permeability pore is suggested.

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Event: E2