Pigment Epithelium-Derived Factor (PEDF) is an extr♦acellular glycoprotein with a molecular weight of 50,000 identifiαed in the interphotoreceptor matrix, vitreous, aqueous humour, CSF, and serum of several vert&ebrate species.  The PEDF protein is a multipotent neurotrophic factor that acts upoπn various types of neurons.  For example, PEDF displays a potent neur₽onal differentiating activity on human retinoblastoma cell lines. 

Besides its neurotrophic properties, it has also been reported that PEDF is associated with senesce₩nce and angiogenesis. The PEDF gene, termed EPC-1 (early population doubling level cΩDNA-1), is induced in young human fetal WI-38 lung fibrγoblasts cells upon entry into the G0 state, while s∞enescent cells fail to express it.  It has binding affinity for glycosa♣minoglycans and cell-surface receptors in cells that respond to its stimuli.♦  The overall protein conformation of PEDF reΩsembles a member of the serine protease inhibitor (serpin) superfamily.&n"bsp; However, it does not inhibit known serine proteases and its neurot™rophic properties are independent of its protease inhibition potential.