| abstract |
The present invention relates to a modified botulinum toxin which has a natural heavy chain and a modified light chain, characterized in that the modification of the light chain consists of (i) at its N-terminus an extension of the chain which in the direction from the N to the C-terminal end has the structure - (C) n - (tag) m - (X) j -, where C for a cysteine residue, day for any day and X represents the remainder of any naturally occurring amino acid, n is an integer from 1 to 50, m is 0 or 1 and Is 10 or an integer from 1 to 50, and (ii) at least one of the cysteine residues in the extension of the chain is coupled to at least one PEG chain. |