Characterization of endothelin-converting enzyme-2. Implication for a role in the nonclassical processing of regulatory peptides.

摘要: Most neuroendocrine peptides are generated by proteolysis of the precursors at basic residue cleavage sites. Prohormone convertases belonging to subtilisin family serine proteases primarily responsible for processing these “classical sites.” In addition classical cleavages, a subset bioactive is “nonclassical” The cleavages have not been well explored. Members several metalloprotease families proposed be involved in nonclassical processing. Among them, endothelin-converting enzyme-2 (ECE-2) good candidate because it exhibits distribution and an acidic pH optimum. To examine involvement this protease neuropeptide processing, we purified recombinant enzyme characterized its catalytic activity. Purified ECE-2 efficiently processes big endothelin-1 between Trp21 Val22 pH. characterize substrate specificity ECE-2, used mass spectrometry with panel 42 as substrates identify products. Only 10 were processed ECE-2. A comparison residues around site revealed that unique selectivity related but distinct from ECE-1. tolerates wide range amino acids P1-position prefers aliphatic/aromatic P1′-position. However, only small fraction acid-containing sites cleaved, indicating there additional constraints beyond P1- P1′-positions. able generate number biologically active peptide intermediates, suggesting important role biosynthesis regulatory peptides. Also, proenkephalin-derived bovine adrenal medulla peptides, leads products known differential receptor selectivity. Finally, PEN-LEN, endogenous inhibitor prohormone convertase 1, into do inhibit enzyme. Taken together, results consistent