New transport protein (A) obtained by modification of the heavy chain of a neurotoxin produced by Clostridium botulinum. Compared with the native neurotoxin (nNT) it: (a) binds with higher or lower affinity to nerve cells； (b) has higher/lower neurotoxicity, particularly as determined in the hemidiaphragm assay； and/or (c) has lower affinity for neutralizing antibodies. Independent claims are also included for the following: (1) composition (C) comprising (A) and at least one intervening compound； (2) method for producing (A) or (C) by standard recombinant methods； (3) host cells that contain a recombinant expression vector (EV) encoding (A) or (C)； and (4) EV. ACTIVITY : Relaxant； Antimigraine； Analgesic； Vulnerary； Antidepressant； Virucide. No details of tests for these activities are given. MECHANISM OF ACTION : Delivering agents that inhibit release of neurotransmitters.
