Abstract: The present invention relates to a recombinant E. coli strain characterized in that the organisms contains a gene coding for a protein having esterase activity. Such E. coli is suitable for the preparation of a protein with esterase activity, whereby the expression takes place without coexpression of GroEL and/or GroES from a plasmid. The expression of glutathione reductase and/or thioredoxin reductase may be abolished by mutation. Furthermore, the ability of the organism to grow under oxygen-rich conditions has been restored by mutation. The expression of the gene of the protein with esterase activity is unaccompanied by the expression of an additional gene encoding a heat shock chaperone protein.

Abstract: The invention relates to an isolated polypeptide having esterase activity comprising an amino acid sequence shown in any one of SEQ ID NO's 2, 4, 6, 8, 10, 12 or 14 or a homologue thereof, comprising an amino acid substitution or deletion of one or more amino acids as shown in said SEQ ID NO's and resulting in a mutant polypeptide having an increased concentration of the fraction of the mutant polypeptide being present as an active and soluble protein in cleared lysate of the mutant polypeptide expressed in E. coli relative to the concentration of the fraction of the polypeptide without the mutation being present as an active and soluble protein in cleared lysate of the polypeptide without the one or more deletion or substitution expressed in E. coli under the same conditions. The invention also relates to nucleic acid encoding the polypeptides according to the invention, and the use of the polypeptides.

Abstract: The invention relates to an isolated polypeptide having esterase activity comprising an amino acid sequence shown in any one of SEQ ID NO's 2, 4, 6, 8, 10, 12 or 14 or a homologue thereof, comprising an amino acid substitution or deletion of one or more amino acids as shown in said SEQ ID NO's and resulting in a mutant polypeptide having an increased concentration of the fraction of the mutant polypeptide being present as an active and soluble protein in cleared lysate of the mutant polypeptide expressed in E. coli relative to the concentration of the fraction of the polypeptide without the mutation being present as an active and soluble protein in cleared lysate of the polypeptide without the one or more deletion or substitution expressed in E. coli under the same conditions. The invention also relates to nucleic acid encoding the polypeptides according to the invention, and the use of the polypeptides.

Abstract: The present invention relates to a recombinant E. coli strain characterized in that the organisms contains a gene coding for a protein having esterase activity. Such E. coli is suitable for the preparation of a protein with esterase activity, whereby the expression takes place without coexpression of GroEL and/or GroES from a plasmid. The expression of glutathione reductase and/or thioredoxin reductase may be abolished by mutation. Furthermore, the ability of the organism to grow under oxygen-rich conditions has been restored by mutation. The expression of the gene of the protein with esterase activity is unaccompanied by the expression of an additional gene encoding a heat shock chaperone protein.