title: Conformational studies of equilibrium structures in fragments of horse heart cytochrome c.
abstract: Ultraviolet absorption and circular dichroism studies have been carried out on horse heart apo-cytochrome c and heme-free peptide fragments obtained by cyanogen bromide cleavage of the native protein. It was noted that the various peptides assume predominantly an unordered conformation in water solution. Increasing ionic strength and addition of 2-chloroethanol increase the right-handed helical content. Guanidinium hydrochloride favors the coil state. It was also demonstrated that two non-interacting helical regions of different stability are present in the apo-protein in 2-chloroethanol.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002942:Circular Dichroism; D003488:Cyanogen Bromide; D003574:Cytochrome c Group; D000431:Ethanol / Q000031:analogs & derivatives; D006146:Guanidines; D006736:Horses; D009206:Myocardium / Q000201:enzymology*; D009994:Osmolar Concentration; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000596:Amino Acids; D003574:Cytochrome c Group; D006146:Guanidines; D010446:Peptide Fragments; D000431:Ethanol; D003488:Cyanogen Bromide