the present invention provides a process for the expression in appropriate host cells of recombinant dna which is under the control of an inducible promotor . in order to obtain the soluble form of recombinant protein , which would usually be obtained in insoluble form , the induction of the promotor is limited to less than 10 % of the maximum induction in comparison with a standard system and the transcription rate of the dna coding for the protein is correspondingly limited .