Absorption UV-VIS and pre-resonance Raman spectra of acidic cyt c solutions with a series of thiols added (thiophenol, n-propanethiol, isopropanethiol, L-cysteine, dithiothreitol, 2-mercaptoethanol, N-acetyl-L-cysteine, p-acetamidothiophenol, 2-mercaptoethanamine, thioglycolic acid and mercaptopropionic acid), are presented. Interactions of cyt c molecule with the thiols were studied with the aim to identify binding of the thiols with the cyt c heme as its iron axial ligands. Absorption and Raman spectra showed some correlation between maxima of 700 nm region absorption band (typical for Fe-S axial bond in cyt c heme) and also wave numbers of spin state marker and axial ligand sensitive Raman bands on one, and pKa constant values of appropriate thiols on the other hand. These results imply thiol replacement of Met-80 from axial bond with heme iron and suggest that the force of Fe-L-cysteine axial bond is very close to the native axial bond (Fe-Met) for cyt c in neutral solution.
- MeSH
- Cytochrome c Group chemistry MeSH
- Heme MeSH
- Hydrogen-Ion Concentration MeSH
- Protein Conformation MeSH
- Spectrum Analysis, Raman MeSH
- Spectrophotometry MeSH
- Sulfhydryl Compounds chemistry MeSH
- Protein Binding MeSH
- Structure-Activity Relationship MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
- Names of Substances
- Cytochrome c Group MeSH
- Heme MeSH
- Sulfhydryl Compounds MeSH
