Figure 149

Biosynthesis of mature endothelin-1 (ET-1). The mature ET-1 peptide is produced by a series of biochemical steps. The precursor of active ET is pre-pro ET, which is cleaved by dibasic pair-specific endopeptidases and carboxypeptidases to yield a 39-amino acid intermediate termed big ET-1. Big ET-1, which has little vasoconstrictor activity, is then converted to the mature 21-amino acid ET by a specific endopeptidase, the endothelin-converting enzyme (ECE). ECE is localized to the plasma membrane of endothelial cells. The arrows indicate sites of cleavage of pre-pro ET and big ET.


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