111 - Endothelin-converting enzyme 2

Abstract

Publisher Summary This chapter reviews the structural chemistry and the biological aspects of endothelin-converting enzyme 2 (ECE-2). Cattle ECE-2 cDNA encodes a 787-amino acid peptide. It is a type II integral membrane protein with a short N-terminal cytoplasmic tail, a transmembrane domain and a large extracellular C-terminal domain. The extracellular region includes the putative catalytic domain that contains the zinc-binding motif. ECE-2 has 10 sites in the extracellular domain predicted to be N-glycosylated. Its highly glycosylated nature, like that of ECE-1, is evident from immunoblot analysis, which shows that ECE-2 is expressed as an approximately 130 kDa protein. The predicted molecular mass based on amino acid content alone is 89 kDa. ECE-1, neprilysin and human Kell group protein show significant sequence similarity to ECE-2. The amino acid sequence of ECE-2 is most similar to that of ECE-1, with an overall identity of 59%. The sequence similarity is especially high within the C-terminal one-third of the putative extracellular domain. Within this region, the identities of ECE-2 with ECE-1, neprilysin and Kell are 71, 44 and 40%, respectively. Characterization of the mRNA for human ECE-2 shows that there are two splice variants and the gene is localized to chromosome 3q28–q29.