BDNF is a member of the nerve growth factor family of trophic factors. In the brain BDNF has a trophic action on retinal, cholinergic, and dopaminergic neurons, and in the peripheral nervous system it acts on both motor and sensory neurons. Some protein domains of BDNF are identical with those of NGF and another neurotrophic factor, designated NT-3 (neurotrophin-3). It exists as monomers and homodimers, and binds to NTRK2/TRKB. Polyclonal antibodies raised against murine NGF have been shown to cross-react with both NT-3 and BDNF. The propeptide is N-glycosylated and glycosulfated. BDNF is converted into mature BDNF by plasmin (PLG). It is expressed in brain, and highly expressed in hippocampus, amygdala, cerebral cortex and cerebellum; it is also expressed in heart, lung, skeletal muscle, testis, prostate and placenta. Recombinant Human Brain-Derived Neurotrophic Factor produced in E.coli is a homodimer, non-glycosylated, polypeptide chain containing 2 x 119 amino acids and having a total molecular mass of 26,984 Daltons.