State the name of the respiratory chain pigment contained in
mitochondria.
The respiratory chain pigment found in the mitochondria is called cytochrome c. It is
a small water-soluble protein found in the intermembrane space of the
mitochondrion. Cytochrome c plays a crucial role in the electron transport chain
(ETC) of the oxidative phosphorylation process in mitochondria.
During oxidative phosphorylation, electrons are transferred through the ETC
embedded in the inner mitochondrial membrane, leading to the generation of a
proton motive force that fuels the synthesis of ATP. Cytochrome c serves as a
mobile electron carrier and shuttles electrons between Complex III and Complex IV
in the electron transport chain, facilitating the production of ATP at the end of the
chain.
Mutations in the gene encoding cytochrome c can lead to various diseases, including
Leigh syndrome, myopathy, and mitochondrial encephalomyopathy. Changes in
cytochrome c levels or its location can also affect apoptosis, a process of
programmed cell death, by inducing apoptosis in some cases, or inhibiting apoptosis
in others. Therefore, cytochrome c is a critical molecule in the mitochondrial
respiratory chain and plays important roles in cell death and disease.
References:
1. Bhattacharya S. et al. Cytochrome c oxidase: subunit composition, assembly, and
function. Encyclopedia of Biological Chemistry. 2013; 325-331.
2. Kadenbach B. Intrinsic and extrinsic uncoupling of oxidative phosphorylation. Biochimica
et Biophysica Acta (BBA)-Bioenergetics. 2003; 1604(2):77-94.
3. Shao J. et al. Cytochrome C oxidase and heart disease. Current Opinion in Cardiology.
2013; 28(3):234-239.