NONGLYCOSYLATED POLYPEPTIDE SHOWING PROPERTY OF PROUROKINASE, METHOD OF ITS PREPARING, RECOMBINANT DNA PLASMID FOR POLYPEPTIDE EXPRESSION AND A METHOD OF ITS PREPARING Russian patent published in 1998 - IPC

FIELD: biotechnology, molecular biology, genetic engineering. SUBSTANCE: method involves transformation of the strain E. coli with recombinant plasmid containing DNA-fragment encoding the end product. Transformants are selected and cultured their under optimal conditions for accumulation of recombinant polypeptide. Polypeptides are separated and expressed product is reactivated. To obtain plasmid for polypeptide expression in enterobacterium cells operon containing regulated promoter with binding sequence with Shine-Delgarno ribosome, initiating codon, DNA-fragment encoding the end polypeptide, one or two terminators disposed after indicated fragment are combined. For combining plasmid pBR 322 no containing nic/bom-region and/or part of tetracycline-resistant gene is used. Site of multiple cloning designed for transcription terminator inserting, DNA-fragment encoding the end polypeptide and synthetic Trp-promoter are incorporated in plasmid between sites Eco RI and HindIII. Polypeptides of the general formula Met-Ser-X₁-X₂-rscu PA 143-411 are obtained. Polypeptide rscu PA 143-411 is a region of amino acid sequence 143 (Glu)-411 (Leu-OH) from scu PA 54k. X₁ means one of amino acids Asn, Pro or Ser and X₂ means simple bond or Glu, or Pro-Glu, or Pro-Pro-Glu, or Glu-Leu-His-Leu-Leu-Gln-Val-Pro-Ser. Obtained polypeptides show high amidolytic and fibrinolytic activity and can be used as plasminogenic activators. EFFECT: improved method of preparing, increased specific activity. 11 cl, 13 dwg