Peroxidase activity of cytochrome c facilitates the protoporphyrinogen oxidase reaction.

Shepherd, Mark and Dailey, Harry A. (2009) Peroxidase activity of cytochrome c facilitates the protoporphyrinogen oxidase reaction. Cellular and Molecular Biology, 55 (1). pp. 6-14. ISSN 1165-158X. (The full text of this publication is not available from this repository)

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Official URL
http://dx.doi.org/10.1170/T831

Abstract

Protoporphyrinogen oxidase (PPO) catalyzes the penultimate reaction in heme biosynthesis. The 'oxygen dependent' form of this enzyme can utilize three molecules of oxygen as electron acceptors in the reaction. In the current study, the ability of cytochrome c to serve as an electron acceptor for PPO was examined. Cytochrome c was found to enhance the catalytic rate of Drosophila melanogaster PPO under reduced oxygen conditions, and cytochrome c became reduced during PPO catalysis. Further kinetic analysis under anaerobic conditions revealed that hydrogen peroxide, a byproduct of the PPO reaction, is required for this rate enhancement to occur. This suggests that the generation of free radicals via the peroxidase activity of cytochrome c plays a part in this rate enhancement, rather than cytochrome c acting as an electron acceptor for the PPO reaction. Given the abundance of cytochrome c in the intermembrane space of mitochondria, the cellular location of PPO, this process may potentially impact on the synthesis of heme in vivo particularly in conditions of low oxygen or hypoxia.

Item Type: Article
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: Mark Shepherd
Date Deposited: 01 Sep 2011 15:56
Last Modified: 30 Jun 2014 14:24
Resource URI: http://kar.kent.ac.uk/id/eprint/28100 (The current URI for this page, for reference purposes)
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