Biosynthesis of the Tachykinins and Somatostatin
Tissue-specific RNA splicing of a single gene transcript may result in the generation of messenger RNA (mRNA) species encoding different polypeptide precursors, which may be processed into different products. For example, transcription of the calcitonin gene in thyroid tissue results in the production of a mRNA encoding the calcitonin precursor, whereas in nervous tissue a mRNA encoding the neuropeptide calcitonin gene-related peptide (C6RP) is generated (Rosenfeld et al., 1983; Craig et al., this volume).
Tissue-specific post-translational modifications of a single polypeptide precursor may generate different polypeptide products. The best known example is pro-opiomelanocortin, the common precursor to adrenocorticotrophic hormone (ACTH), the melanocyte-stimulating hormone (α, β- and γ-MSH) and the endorphin family of opioid peptides. In the anterior pituitary gland, the predominant products of POMC processing are ACTH and β-endorphin, whereas in the pars intermedia αMSH, corticotrophin-like intermediate lobe peptide (CLIP) and acetylated, biologically inactive forms of endorphin are produced (Krieger & Liotta, 1979).
KeywordsHigh Performance Liquid Chromatography Proline Methionine Histidine Phenylalanine
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