The serum glycoprotein a1-antitrypsin also called a1- AT, is a typical member of the serpin family (serine protease inhibitors), and, an inhibitor of trypsin. a1- AT is synthesized in the liver thus as a single polypeptide chain of appro, Xenopus/Amphibian,imately 51 kDa showing a marked degree of genetic polymorphism due to the presence of over 20 different alleles. Individuals homozygous for a1- AT deficiency are predisposed to pulmonary emphysema and hepatic cirrhosis. This antibody is specific for human a1- AT (native and denatured).