High-yield production of recombinant endothelin-1

A fusion protein (pETB-42P), which encodes the 42-amino acid leader peptide and the 38-amino acid peptide of human big endothelin (ET)-1, was synthesized in Escherichia coli, isolated as inclusion bodies, and purified by DEAE-chromatography. Trypsin digestion of the purified pETB-42P gave big ET-1(1-37) in a yield of 70%; then pepsin digestion of the purified big ET-1(1-37) gave ET-1(1-21) in a yield of 74% (overall yield: 52%). Sequential trypsin and pepsin digestions of the purified fusion protein in the same reaction vessel also allowed recovery of ET-1 in a yield of 60%. One milligram of ET-1 or 2.0 mg of big ET-1(1-37) was obtained from 1.8 liters of culture broth. Recombinant ET-1 thus obtained was identical to authentic ET-1 in terms of amino acid sequence and vasoconstrictor potency, and recombinant big ET-1(1-37) had almost the same in vitro and in vivo biological activities as big ET-1(1-38).