Stromal Cell-Derived Factor-1 (SDF-1) is a chemokine member of the intercrine family. SDF1 is expressed as five isoforms that differ only in the C terminal tail. SDF1α and SDF1β are identical except for the four residues present in the C-terminus of SDF1β but absent from SDF1α. SDF1 isoforms interact with CXCR4 and CXCR7 receptors on the cell surface, and can also bind syndecan4. SDF1 is known to influence lymphopoiesis, regulate patterning and cell number of neural progenitors, and promote angiogenesis. It also enhances the survival of myeloid progenitor cells.

> 95% as determined by SDS-PAGE