This polyclonal antibody was generated against a purified His-tagged 20 kDa C-terminal fragment of CPD (aa 1169 – 1347) expressed in E. Coli and is specific for the C-terminal 179 amino acids of human and mouse CPD. Carboxypeptidase D (CPD) is a membrane glycoprotein with a single hydrophobic transmembrane anchor near the C-terminus and three tandem carboxypeptidase homology domains. Domains 1 and 2 are catalytically active but domain 3 is not. CPD cleaves only C-terminal Arg or Lys residues from proteins and has an acidic pH optimum of ~ 6.0. CPD is ubiquitously expressed and is especially high in macrophages. CPD is predominantly localized in the trans-Golgi and is involved in peptide and protein processing in the constitutive secretory pathway after initial furin cleavage and is also involved in processing microbial toxins such as Pseudomonas exotoxin. Drosophila lacking CPD die in the larval stage and CPD is an important target gene of TGF-ß in macrophages that is downregulated in lupus erythematosus. CPD-mediated generation of L-Arg enhances iNOS-dependent NO generation in mouse macrophages and promote NO production and cell survival in breast cancer cells.