title: Modulation of the alkaline transition in cytochrome c and cytochrome c-T by full or specific partial acetimidylation.
abstract: Acetimidylated horse cytochrome c and related derivatives exhibit more or less marked changes, both upscale and downscale, in apparent pK of the alkaline transition. This transition occurs when the normal methionine-80 residue is replaced at the sixth haem co-ordination position by another strong-field ligand. Analysis of the relationship between structural change and pK shift in these derivatives supports the view that the replacement ligand is a lysine residue, probably 72 or 79, and contradicts an alternative hypothesis. The results add further detail to a comprehensive view of the mechanism of this isomerization.
mesh_terms: D000468:Alkalies; D055598:Chemical Phenomena; D002621:Chemistry; D003574:Cytochrome c Group / Q000031:analogs & derivatives*; D045304:Cytochromes c; D008024:Ligands; D009994:Osmolar Concentration; D010446:Peptide Fragments; D013053:Spectrophotometry
chemical_list: D000468:Alkalies; D003574:Cytochrome c Group; D008024:Ligands; D010446:Peptide Fragments; C040819:cytochrome c, N-epsilon-acetimidate; D045304:Cytochromes c; C040820:cytochrome c-T