Chymase inhibitor-sensitive synthesis of endothelin-1 (1-31) by recombinant mouse mast cell protease 4 and human chymase.

Important structural differences imply that human and mouse mast cell chymases may differ with respect to their enzymatic properties. We compared in this study the catalytic efficiencies of recombinant human chymase (rCMA1) and its functional murine homologue recombinant mouse mast cell protease-4 (rmMCP-4) toward a fluorogenic chymase substrate (Suc-Ala-Ala-Pro-Phe-7-amino-4-methylcoumarin (AMC) and by their ability to convert Big-endothelin (ET)-1 into ET-1 (1-31) using a LC/MS/MS system. Activities toward a fluorogenic substrate (Suc-Leu-Leu-Val-Tyr-AMC) and Big ET-1 were also measured in extracts from mouse peritoneal mast cells, LUVA human mast cell-like cells and human aortas.