Purity: > 90% by SDS - PAGE Format: Liquid. In 20mM Tris-HCl buffer (pH8.0) containing 20% glycerol.. PEDF, also known as SERPINF1, is an extracellular neurotrophic agent, first identified as a secreted product in conditioned medium from cultured fetal human retinal pigment epithelial (RPE) cells. It was reported that PEDF isolated from medium conditioned by human fetal RPE primary cultures promotes neurite outgrowth in cultured human retinoblastoma Y-79 cells. PEDF is also a member of the serpin family, a group of serine protease inhibitors. As PEDF does not undergo the S (stressed) to R (relaxed) conformational transition characteristic of active serpins, it exhibits no serine protease inhibitory activity. Recombinant PEDF protein containing a natural variant M72T was expressed in E.coli and purified by using conventional chromatography techniques.