Mouse Serpin A1c/ alpha1-Antitrypsin Antibody

SerpinA1c (serine proteinase inhibitor-clade A 1c; also alpha-1 protease inhibitor 6 and alpha1 antitrypsin 1-3) is a secreted, 50-55 kDa glycoprotein member of the clade A-subfamily, serpin superfamily of protease inhibitors. There are multiple sources for serpinA1. The circulating form of serpinA1 is expressed by hepatocytes, while local production occurs in the bone marrow by osteoblasts, PMNs, T cells and B cells. SerpinA1 is a naturally occurring serine protease inhibitor. Its principal activity seems to be that of neutralizing neutrophil elastase, an activity that protects the elasticity of the lung during inflammation. It is also posited to play a role in bone marrow progenitor mobilization. Here, it promotes HPC proliferation by blocking cytokine degradation, and interferes with HPC migration by blocking protease cleavage of engaged cell adhesion molecules. Mature mouse serpinA1c is 389 amino acids (aa) in length (aa 25-413) (GenBank#:NP_033271) and contains one active enzymatic site (aa 67-410). Unlike human and rat, the mouse genus contains anywhere from one to seven serpinA1genes. Mus caroli (an Asian species) possesses one gene, Mus saxicola (a south asia species) possesses four genes, and Mus musculus possesses six or more distinct genes. Within Mus musculus, various strains have variable numbers of active genes. While highly homologous, the protein sequences are not identical, and differ most importantly in the reactive center loop region (aa 374-386). The protein referenced here is equivalent to alpha1-PI-3 (Borriello, F & K.S. Krauter [1991] Proc. Natl. Acad. Sci. USA 88:9417). This gene has one isoform with minimal scattered substitutions and shows more that 98% aa sequence identity (GenBank #:Q00896). Over aa 25-413, serpinA1c/ alpha1-IP-3 shares 97% and 95% aa sequence identity with serpinA1a/ alpha1-PI-1 and serpinA1b/ alpha1-IP-2, respectively. It also shares 77% and 64% aa sequence identity with rat and human serpinA1, respectively.