Abstract: A method of extracting a cytoplasmic or periplasmic protein. The method comprises provision of a first cell suspension comprising cells, the cells containing a cytoplasmic or periplasmic protein of interest to be extracted, the first cell suspension having a first temperature, and heating of the first cell suspension to an operating temperature, at which operating temperature at least a fraction of the cells is subject to heat-induced lysis and at least a fraction of the cytoplasmic or periplasmic protein of interest to be extracted is not subject to irreversible denaturation. The heating of the first cell suspension comprises provision of an aqueous solution, the aqueous solution having a second temperature that is higher than the first temperature, and mixing of the first cell suspension with the aqueous solution, thereby obtaining a second cell suspension, the second cell suspension having a third temperature that is higher than the first temperature.

Abstract: This invention relates to an apparatus for automatic purification of extra-chromosomal DNA from a cell suspension in a container. The apparatus comprises a device for introducing the cell suspension from a container into a chamber; a device for agitating the contents of the chamber; a device for introducing a lysing solution to the chamber to lyse the cells therein; a device for introducing a precipitating solution into the chamber to precipitate chromosomal DNA and, optionally, proteins and cellular debris therein; a device for feeding the liquid contents of the chamber through a filter to a collecting system; a device for purifying extra-chromosomal DNA from the contents of the collecting device; a device for introducing a dissolving solution into the chamber to dissolve the precipitate remaining therein, and a device for feeding the dissolved precipitate to waste.

Abstract: A process for expressing proteins in Gram(-) bacteria and providing for extracellular secretion thereof, comprising the steps: a) introducing into a Gram(-) bacterium a recombinant DNA construction comprising a promoter, a signal sequence enabling translocation and processing, and a structural gene encoding the desired protein to be expressed; b) cultivating the bacterium under conditions resulting in filamentous growth; and c) recovering the extracellularly secreted protein; a recombinant DNA construction comprising:a promoter, a signal sequence and a structural gene including a cleavage region,wherein the structural gene is of the formula:(E).sub.n (B).sub.m -Y,where n is an integer .gtoreq.

Abstract: A recombinant DNA fragment (Z) coding for an immunoglobulin G binding domain related to staphylococcal protein A. The methionine codon of the recombinant DNA fragment has been replaced with a codon of an amino acid residue other than methionine to enable expression of a methionine-free protein. The present invention is also directed to recombinant DNA sequence containing such recombinant DNAS fragment (Z) as well as a recombinant DNA molecule, plasmid vector and bacterial cell containing such recombinant DNAS fragment. Also disclosed is a process for cleaving a fused protein expressed in a biological system using said recombinant DNA fragment.