BDNF, also known as brain-derived neurotrophic factor and abrineurin, is a neurotrophin belonging to the NGF-beta family. It is expressed highly in the brain, and moderately in the heart, lung, skeletal muscle and placenta. BDNF signals through its high affinity receptor gp145/trkB to exert neurotrophic properties. It has been shown to be involved in the survival and differentiation of both the central and peripheral nervous system. Specifically, BDNF regulates synaptic transmission, axonal growth and path-finding, as well as dendritic growth and morphology.

> 95% as determined by SDS-PAGE