Preparation of biologically active beta-NGF comprises denaturing its inactive insoluble proform followed by renaturation and pro-sequence cleavage. Preparation of biologically active beta -NGF from its inactive insoluble proform, obtained by recombinant preparation in prokaryotic cells comprises: (a) dissolving ProNGF in its inactive insoluble form in a denaturating solution ； (b) transferring into a non- or weak denaturing solution where the denatured proNGF assumes a biologically active conformation, determined by the presence of disulfide bridges occurring in natural beta -NGF； and (c) cleaving the pro-sequence to obtain the active beta -NGF followed by its isolation.
