Purification, primary structure, and biological activity of guinea pig neutrophil cationic peptides.

The guinea pig neutrophil cationic peptides GNCP-1 and GNCP-2 were purified from a granule-rich subcellular fraction of peritoneal exudate neutrophils by acid-gel electrophoresis and reversed-phase high-performance liquid chromatography. Both peptides not only released histamine from rat mast cells to the same extent but also were equally active against Staphylococcus aureus and Escherichia coli. The peptides were rich in arginine and cystine and lacked free sulfhydryl groups. Composition and sequence determinations revealed that GNCP-1 and GNCP-2 are each single polypeptides containing 31 amino acid residues and three intramolecular disulfide bonds. The complete amino acid sequence of GNCP-1 is Arg-Arg-Cys-Ile-Cys-Thr-Thr-Arg-Thr-Cys-Arg-Phe-Pro-Tyr-Arg-Arg-Leu-Gly- Thr-Cys - Ile-Phe-Gln-Asn-Arg-Val-Tyr-Thr-Phe-Cys-Cys. The sequence of GNCP-2 is identical except for the substitution of isoleucine for leucine at residue 21.