Structure and Post-Translational Processing of the Preprotachykinins
Substance P is synthesised from two precursors, α and β preprotachykinin (PPT), which are derived from a single gene by differential RNA splicing [1,2]. We have recently elucidated the cDNA sequence of human β-PPT. The human β-PPT polypeptide contains, in addition to a region encoding SP, the sequences of neurokinin A (NkA) and of neuropeptide K (NpK), an N-terminally extended form of NkA first isolated from porcine brain . We are presently searching for novel fragments of α- and β-PPT which may exhibit biological activity. Rat brain contains a 5,500 Mol. Wt. form of NkA-like immunoreactivity which apparently contains antigenic determinants related to both SP and NkA. This peptide may represent an intermediate in the post-translational processing of β-PPT.
KeywordsSubstantia Nigra Carcinoid Tumour Porcine Brain Signal Peptidase Cleavage Site Royal Edinburgh Hospital
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