Functional activities of synthetic anaphylatoxic peptides in widely used biological assays.
A comparison study was carried out between the modern ATP release assay (ARA) with guinea-pig platelets and the traditional guinea-pig ileum contraction assay (ICA). The biological activities of the anaphylatoxin C3a and synthetic C3a analogue peptides were determined in both assays. In dose-response curves with C3a, a human C3a peptide with the last 21 amino acids of the C terminus (C3a 56-77) and a peptide with 13 amino acids which was acylated N-terminal with the aromatic fluorenylmethoxycarbonyl group and an aminohexanoyl group (Fmoc-Ahx YRRGRAAALGLAR) were tested. The ARA turned out to be 100 times more sensitive than the ICA. In contrast to previous reports the 21 amino acid long C3a analogue peptide did not exhibit full C3a activity but only 7% (ARA) or 12% (ICA). The potentiation of biological activity in the ARA by coupling non-peptide acyl-residues N terminal to peptide C3a analogues could be confirmed with Fmoc-Ahx-YRRGRAAALGLAR in the ICA. In addition, the tri-peptide Fmoc-Ahx-LAR displayed C3a specific activity in the ICA demonstrated by desensitization experiments.
Kola
A
A
Department of Medical Microbiology, Hannover Medical School, Germany.
Klos
A
A
Bautsch
W
W
Kretzschmar
T
T
Köhl
J
J
D000255:Adenosine Triphosphate / Q000097:blood; D000595:Amino Acid Sequence; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D015926:Complement C3a / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects
D015926:Complement C3a; D000255:Adenosine Triphosphate