Isolation and characterization of neurokinin A, neurokinin A(3-10) and neurokinin A(4-10) from a neutral water extract of a metastatic ileal carcinoid tumour.
A metastasis to the right liver lobe of an argyrophil/argentaffin midgut carcinoid tumour in a patient with the classical carcinoid syndrome was examined for the presence of tachykinins other than substance P, using a specific antiserum. The extract was initially purified using SepPak cartridges, and subsequently subjected to cation-exchange chromatography on SP Sephadex C-25 which separated the immunoreactive material into two main components (components I and II). Both were further purified by anion-exchange chromatography on DEAE-Sephadex A-25, and by reverse-phase fast protein liquid chromatography. Component II was identified as neurokinin A by its immunochemical and chromatographic properties and amino acid sequence analysis. Component I consisted of two molecular forms which were identified as neurokinin A(3-10) and neurokinin A(4-10) by amino acid sequence analysis. The tumour tissue contained only small amounts of the eledoisin-like peptide that has earlier been demonstrated in mammalian tissues. Although this component behaved like the nonmammalian peptide eledoisin on reverse-phase HPLC and on reverse-phase ion-pair chromatography, eledoisin-specific antiserum E2 indicated that eledoisin-like peptide is not identical to eledoisin. Neurokinin A in carcinoid tumours has an N-terminal heterogeneity; this multiplicity constitutes a further support for the hypothesis that carcinoid tumours produce a number of tachykinins which may be present in different relative amounts in individual patients and may contribute to the individual differences in symptomatology.
D002276:Carcinoid Tumor / Q000032:analysis* / Q000556:secondary; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006801:Humans; D007078:Ileal Neoplasms / Q000032:analysis*; D008113:Liver Neoplasms / Q000032:analysis / Q000556:secondary; D015288:Neurokinin A; D009479:Neuropeptides / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000302:isolation & purification; D011863:Radioimmunoassay; D012995:Solubility; D014867:Water
D009479:Neuropeptides; D010446:Peptide Fragments; D014867:Water; D015288:Neurokinin A