Patent ID: 6844169

Claim:
Method for producing a recombinant protein wherein a gene encoding the protein is placed under the control of the Ptrp trytophan operon promoter, wherein the method comprises the following steps: a) transforming a prokaryotic cell with a vector containing a nucleic acid sequence which is capable of inactivating the gene encoding a TnaA tryptophanase when said nucleic acid sequence is introduced into said host cell, and integrating said sequence into the DNA of said host cell; and before-hand, subsequently or simultaneously, introducing into said prokaryotic cell all or part of the sequence of a promoter which is followed, in the 3′ position, by a nucleic acid sequence encoding a molecule which is ribonucleotide or protein in nature, and which acts negatively on the Ptrp promoter or its transcription product; b) transforming said prokaryotic cell with a vector containing a gene encoding said recombinant protein; c) culturing said transformed cell in a culture medium which allows the expression of the recombinant protein; and d) recovering the recombinant protein from the culture medium or from said transformed cell.