Abstract: The invention relates to a modified botulinum toxin comprising a natural heavy chain and a modified light chain, characterized in that the modification of the light chain resides in that it comprises (i) an extension of the chain on its N-terminus which has the structure -(C)n-(tag)m-(X)l- in the direction from the N- to the C-terminal end, wherein C represents a cysteine residue, tag represents any tag and X represents the residue of any naturally occurring amino acid, n represents an integer from 1 to 50, m represents 0 or 1, and l represents 0 or an integer from 1 to 50, and in that (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one chain of PEG.

Abstract: The invention relates to a modified botulinum toxin comprising a natural heavy chain and a modified light chain, characterized in that the modification of the light chain resides in that it comprises (i) an extension of the chain on its N-terminus which has the structure -(C)n-(tag)m-(X)l- in the direction from the N- to the C-terminal end, wherein C represents a cysteine residue, tag represents any tag and X represents the residue of any naturally occurring amino acid, n represents an integer from 1 to 50, m represents 0 or 1, and l represents 0 or an integer from 1 to 50, and in that (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one chain of PEG.

Abstract: The invention relates to a modified botulinum toxin comprising a natural heavy chain and a modified light chain, characterized in that the modification of the light chain resides in that it comprises (i) an extension of the chain on its N-terminus which has the structure —(C)n-(tag)m-(X)l— in the direction from the N- to the C-terminal end, wherein C represents a cysteine residue, tag represents any tag and X represents the residue of any naturally occurring amino acid, n represents an integer from 1 to 50, m represents 0 or 1, and l represents 0 or an integer from 1 to 50, and in that (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one chain of PEG.

Abstract: The invention relates to a modified botulinum toxin comprising a natural heavy chain and a modified light chain, characterized in that the modification of the light chain resides in that it comprises (i) an extension of the chain on its N-terminus which has the structure —(C)n-(tag)m-(X)l- in the direction from the N- to the C-terminal end, wherein C represents a cysteine residue, tag represents any tag and X represents the residue of any naturally occurring amino acid, n represents an integer from 1 to 50, m represents 0 or 1, and l represents 0 or an integer from 1 to 50, and in that (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one chain of PEG.

Abstract: The invention relates to a modified botulinum toxin comprising a natural heavy chain and a modified light chain, characterized in that the modification of the light chain resides in that it comprises (i) an extension of the chain on its N-terminus which has the structure —(C)n-(tag)m-(X)l— in the direction from the N- to the C-terminal end, wherein C represents a cysteine residue, tag represents any tag and X represents the residue of any naturally occurring amino acid, n represents an integer from 1 to 50, m represents 0 or 1, and l represents 0 or an integer from 1 to 50, and in that (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one chain of PEG.

Abstract: The invention relates to a modified botulinum toxin comprising a natural heavy chain and a modified light chain, characterized in that the modification of the light chain resides in that it comprises (i) an extension of the chain on its N-terminus which has the structure —(C)n-(tag)m-(X)l— in the direction from the N- to the C-terminal end, wherein C represents a cysteine residue, tag represents any tag and X represents the residue of any naturally occurring amino acid, n represents an integer from 1 to 50, m represents 0 or 1, and l represents 0 or an integer from 1 to 50, and in that (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one chain of PEG.

Abstract: The invention relates to a modified botulinum toxin comprising a natural heavy chain and a modified light chain, characterized in that the modification of the light chain resides in that it comprises (i) an extension of the chain on its N-terminus which has the structure —(C)n-(tag)m-(X)l— in the direction from the N- to the C-terminal end, wherein C represents a cysteine residue, tag represents any tag and X represents the residue of any naturally occurring amino acid, n represents an integer from 1 to 50, m represents 0 or 1, and l represents 0 or an integer from 1 to 50, and in that (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one chain of PEG.

Abstract: Polypeptides or proteins are produced as a disulfide bridged dichain by recombinant expression in E. coli host cells and exert biologic activity as such a dichain. A C-terminal amino acid of the first chain is Arg or Lys. The second chain has N-terminally 1 to 20 amino acid residues and a PRS sequence VPXGS, wherein X is a natural amino acid; V is Val, Leu, Ile, Ala, Phe, Pro or Gly; P is Pro, Leu, Ile, Ala, Phe, Val or Gly; G is Gly, Leu, Ile, Ala, Pro, Phe or Val; S is Ser, Tyr, Trp, or Thr. The polypeptide/protein is modified at the nucleic acid level to a construct that in a loop area has a PRS sequence VPXGS with X, V, P, G, and S as defined. The construct is inserted into E. coli host cells that are cultivated and subsequently lysed for isolating the dichain disulfide-bridged peptide/protein.