Abstract: The invention relates to a DNA that enables co-expression of a protein disulfide isomerase and a polypeptide having disulfide bonds. The invention further relates to a process of producing polypeptides using the DNA and a process of enhancing the efficiency of formation of correct disulfide bond in an expression system of a gene recombinant polypeptide having disulfide bonds.

Abstract: This invention relates to a DNA encoding a fusion protein of formula (I) [Y]-[X1]-[B-chain]-[X2]-[Linker]-[X3]-[A-chain]??(I) wherein Y is a leader peptide sequence for the expression and secretion of the protein, comprising at least one amino acid residue; X1 is an amino acid sequence which is cleavable enzymatically or chemically; B-chain is the amino acid sequence of insulin B chain; X2 is an amino acid sequence which is cleavable enzymatically; Linker is a linker sequence comprising at least one amino acid residue; X3 is an amino acid sequence which is cleavable enzymatically; and A- chain is the amino acid sequence of insulin A chain, and to a method for producing insulin using an expression system containing the DNA in high efficiency and high yield.

Abstract: The present invention relates to a DNA which enables co-expression of a protein disulfide isomerase and a polypeptide having disulfide bonds,

Abstract: This invention relates to a DNA comprising a nucleotide sequence encoding a fusion protein, wherein the fusion protein comprises: a sequence of signal peptide for Bacillus cell wall protein (CWP); a tag sequence for separation and purification of the fusion protein; a linker sequence; a sequence for chemical or enzymatic cleavage; and an exogenous polypeptide sequence, the sequences being linked in order, the signal peptide, tag and linker being optional sequences; and wherein the nucleotide sequence encoding a fusion protein is ligated to 3′-end of a nucleic acid sequence comprising a Bacillus promoter region; to a vector comprising the DNA; to a bacterium belonging to the genus Bacillus comprising the vector; and to a process for preparation of a useful polypeptide by culture of the bacterium.

Abstract: This invention relates to a DNA comprising a nucleotide sequence encoding a fusion protein, wherein the fusion protein comprises: a sequence of signal peptide for Bacillus cell wall protein (CWP); a tag sequence for separation and purification of the fusion protein; a linker sequence; a sequence for chemical or enzymatic cleavage; and an exogenous polypeptide sequence, said sequences being linked in order, said signal peptide, tag and linker being optional sequences; and wherein said nucleotide sequence encoding a fusion protein is ligated to 3′-end of a nucleic acid sequence comprising a Bacillus promoter region; to a vector comprising the DNA; to a bacterium belonging to the genus Bacillus comprising the vector; and to a process for preparation of a useful polypeptide by culture of the bacterium.