High-level production of biologically active human alpha 1-antitrypsin in Escherichia coli.

Abstract
A c[complementary]DNA clone containing the complete human .alpha.1-antitrypsin sequence was isolated from a human liver cDNA bank by screening with a chemically synthesized oligonucleotide probe. DNA sequences encoding the .alpha.1-antitrypsin mature polypeptide were inserted into an E. coli expression vector that allows transcription from the efficient leftward promoter of bacteriophage .lambda. (PL) and initiation of translation at the .lambda./cII gene ribosome-binding site. This construction resulted in the induction of a 45-kdalton protein at a level of .apprx. 15% of total cell protein. The polypeptide produced was recognized by antisera raised against human .alpha.1-antitrypsin protein and displayed normal biological activity in an in vitro antielastase assay.