CARBOXY TERMINAL FRAGMENT OF HUMAN ALPHA-1-ANTITRYPSIN FROM HYDROXYLAMINE CLEAVAGE - HOMOLOGY WITH ANTITHROMBIN-III

Human α-1-antitrypsin (AT) was reacted with hydroxylamine at pH 9.0 giving cleavage at an Asn-Gly bond. A fragment of molecular weight 8,500 was released and this was isolated and sequenced. The fragment had the same carboxy terminal amino acid sequence as intact AT. The 80 residue polypeptide contained the Z variant mutation site and a portion of sequence identical to that found by others for the reactive site, inferring the presence in AT of two active sites. This sequence combined with prviously published work gives a continuous sequence of 152 amino acid residues from the carboxy terminal end of the AT molecule, including the mutation site of the S variant. The sequence shows strong homology with human antithrombin III. © 1979.