Cytochrome c from human heart

General description

Cytochrome c (CYCS) is mapped to human chromosome 7p15.3. CYCS is a heme protein containing three long α-helices. It undergoes domain swapping at the C-terminus and exists in dimeric, trimeric, and tetrameric forms. Insertion mutations in CYCS is implicated in acute myeloid leukemia. Mutations in CYCS modulates the release of proplatelets and decreases platelet production leading to thrombocytopenia 4.

Application

Cytochrome c from human heart has been used for the generation of standard curves in the electrochemiluminescence assay for measurement of cytochrome C levels in plasma samples and in electrospray ionization mass spectrum (ESI-MS) analysis.

Cytochrome c has been identified as an important mediator in apoptotic pathways. The release of mitochondrial cytochrome c into the cytoplasm stimulates apoptosis and is commonly used as an indicator of the apoptotic process in the cell. Investigation on the effect of Paris Saponin I (PS I) on human gastric carcinoma cell growth (SGC7901 cells) have shown an elevated level cytoplasmic cytochrome c. Results are an inhibition of proliferation in SGC7901 cells by inducing mitochondria-dependent apoptosis through cytochrome c.

Biochem/physiol Actions

The ready fluctuation of cytochrome c within the cell between ferrous and ferric states, makes it an efficient biological electron-transporter. It plays a vital role in cellular oxidations in both plants and animals. Generally regarded as a universal catalyst of respiration, it forms the essential electron-bridge between the respirable substrates and oxygen.

The ready fluctuation of cytochrome c within the cell between ferrous and ferric states, makes it an efficient biological electron-transporter. It plays a vital role in cellular oxidations in both plants and animals. Generally regarded as a universal catalyst of respiration, it forms the essential electron-bridge between the respirable substrates and oxygen.

In addition to its function in electron transport, cytochrome c acts as an apoptosis-triggering agent, forming the apoptosome with apoptosis protease-activating factor-1 (Apaf-1) and activating the caspase cascade. The two functions are finely tuned by phosphorylation of Tyr residues at position 48 and/or 97. One recent report provides suggestive evidence that phosphorylation at Tyr⁴⁸ switches off the apoptotic effect.

Physical form

Lyophilized from a 0.2 μm filtered solution in phosphate buffered saline.

Preparation Note

Chemically oxidized during purification.

Other Notes

View more information on cytochrome c and electron transport at www.sigma-aldrich.com/enzymeexplorer.