Specificity of rabbit antisera for peptide 81-104 of horse cytochrome c is dominated by C-terminal residues.
Sera have been prepared in rabbits against the carboxy terminal cyanogen bromide fragment of horse cytochrome c (81-104) conjugated to bovine serum albumin (BSA). The specificity of these sera has been studied by radioimmunoassay and reveals that only peptide 81-104 binds the antibody. Neither whole cytochrome c nor peptides 1-65 and 66-80 displace 125I-81-104 from specific antibody, while cold peptides 81-104 is active in this regard, as expected. Fine specificity studies with isolated heterologous peptides 81-104 from the bovine, rabbit, canine, chicken, pigeon and tuna species of cytochrome c reveal that a major antigenic determinant is influenced by sequence positions 100 and 103 while a minor antigenic determinant is influenced by residue 92. These results are exactly mirrored and supported by inhibition studies with the isolated chymotryptic fragments 98-104 and 83-97. Studies with tryptic, chymotryptic and peptic digests of horse cytochrome c reveal that these natural proteases can generate peptides with the appropriate peptide sequences to react with antibodies produced against the peptide 81-104-BSA conjugate.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000918:Antibody Specificity; D001667:Binding, Competitive; D002417:Cattle; D002645:Chickens; D002918:Chymotrypsin; D010856:Columbidae; D003574:Cytochrome c Group / Q000276:immunology*; D004285:Dogs; D006736:Horses; D010446:Peptide Fragments / Q000276:immunology*; D011817:Rabbits; D013045:Species Specificity; D014413:Tuna
D000596:Amino Acids; D003574:Cytochrome c Group; D010446:Peptide Fragments; D002918:Chymotrypsin