The present invention relates to a proNGF mutant and to uses thereof, in particular the use of a proNGF mutant for producing human beta-NGF. The present invention discloses a method of preparing a biologically active human beta-NGF from an inactive insoluble proNGF mutant. A proNGF mutant of the invention is substituted by any amino acid but not Arg or Lys at the native protease cleavage site R 1 SK 3 R 4 at least at positions R 1 and K 3 corresponding to positions 101 and 103 of the human wildtype proNGF sequence.
