ProNGF mutants and uses thereof in the production of beta-NGF

A method for preparing a biologically active human beta-NGF comprising:

• providing a proNGF mutant wherein the protease cleavage site R1 SK3 R4 is substituted at least at positions R 1 and K 3 corresponding to positions 101 and 103 of the human wild type proNGF sequence (SEQ ID NO:
• 1) by an amino acid selected from the group consisting of a non-basic amino acid and Histidine;
• and
• cleaving the proNGF mutant to obtain active human beta-NGF.

A method for preparing a biologically active human beta-NGF comprising:

• providing a proNGF mutant wherein the protease cleavage site R1 SK3 R4 is substituted at least at positions R 1 and K 3 corresponding to positions 101 and 103 of the human wild type proNGF sequence (SEQ ID NO:
• 1) by an amino acid selected from the group consisting of a non-basic amino acid and Histidine;
• and
• cleaving the pro-sequence of the proNGF mutant to obtain active human beta-NGF.