Human Meprin  beta  Subunit/MEP1B Alexa Fluor™ Plus 488‑conjugated Antibody

Meprins are multimeric proteases composed of alpha and beta  subunits, which are members of the astacin family of zinc endopeptidases (1, 2). Both subunits form disulfide‑linked homo- or heterooligomers, which are also referred to as Merpin A (composed of alpha  subunits with or without beta  subunits) and Merpin B (composed of beta  subunits only) (3). Although the two subunits share 42% identity in their amino acid sequence, they differ significantly in their oligomeric structure, post-translational processing and subsequently cellular location, and substrate and peptide bond specificity (4). The 701 amino acid sequence of human Merpin beta  subunit precursor consists of a signal peptide (residues 1 to 21), a pro region (residues 22 to 61), and a mature chain (residues 62 to 701) containing the following domains, catalytic (residues 62 to 259), MAM (residues 260 to 429), MATH (residues 430 to 585), EGF-like (residues 604 to 644), transmembrane (residues 653 to 673), and cytoplasmic (residues 674 to 701). The pro enzyme terminating at residue 593 was expressed and the secreted protein purified from conditioned medium. After trypsin treatment, the activated enzyme cleaved a flurogenic peptide, which contains Asp and Glu, the preferred residues found in the P1’ and P1 sites (3).