Neuropeptide‐γ: A Peptide Isolated from Rabbit Intestine that Is Derived from γ‐Preprotachykinin

Abstract: The neurokinin A‐like immunoreactivity in an extract of rabbit small intestine was resolved into two molecular forms by gel permeation chromatography. These components were purified to apparent homogeneity by reverse‐phase HPLC. The primary structure of the larger component was established as the following: Asp‐Ala‐Gly‐His‐Gly‐Gln‐Ile‐Ser‐His‐Lys‐Arg‐His‐Lys‐Thr‐Asp‐Ser‐Phe‐Val‐Gly‐Leu‐Met‐NH₂. This amino acid sequence represents residues (72–92) of γ‐preprotachykinin, as predicted from the nucleotide sequence of a cloned cDNA from the rat. The peptide, termed neuropeptide‐γ, lacks residues (3–17) of neuropeptide K, and this segment is specified exactly by exon 4 in the preprotachykinin gene. The smaller form of neurokinin A‐like immunoreactivity was identical to neurokinin A. Neuropeptide K was not present in the extract, demonstrating that the pathways of post‐translational processing of β‐ and γ‐preprotachykinins in the rabbit gut are different.