Primary sequence characterization of catestatin intermediates and peptides defines proteolytic cleavage sites utilized for converting chromogranin a into active catestatin secreted from neuroendocrine chromaffin cells.

摘要: Catestatin is an active 21-residue peptide derived from the chromogranin A (CgA) precursor, and catestatin secreted neuroendocrine chromaffin cells as autocrine regulator of nicotine-stimulated catecholamine release. The goal this study was to characterize primary sequences high molecular mass intermediates peptides define proteolytic cleavage sites within CgA that are utilized in biosynthesis catestatin. Catestatin-containing polypeptides, demonstrated by anti-catestatin western blots, 54-56, 50, 32, 17 kDa contained NH(2)-terminal indicated cleavages precursor at KK downward arrow, KR R arrow basic residue sites, respectively. COOH termini these were defined presence COOH-terminal tryptic corresponding residues 421-430, which identified MALDI-TOF spectrometry. Results also 54-56 50 contain NH(2) terminus CgA. Secretion accompanied cosecretion (CgA(344)(-)(364)) variant forms (CgA(343)(-)(368) CgA(332)(-)(361)). These determined predicted production requires sides paired residues, compatible with specificities PC1 PC2 prohormone convertases. However, it notable itself utilizes more unusual RR consistent granule cysteine protease "PTP" participates proenkephalin processing. findings demonstrate involves monobasic necessary steps for regulation nicotinic cholinergic-induced