Purity ≥96% as determined by SDS-PAGE and HPLC. Intercellular signal essential for a variety of patterning events during development. Binds to the patched (PTC) receptor, which functions in association with smoothened (SMO), to activate the transcription of target genes. Implicated in endochondral ossification: may regulate the balance between growth and ossification of the developing bones. Induces the expression of parathyroid hormone-related protein (PTHRP) (By similarity). (ECO:0000250). Biological Activity: Fully biologically active when compared to standard. The ED50 as determined by its ability to induce alkaline phosphatase production by C3H10T1/2(CCL-226) cells is 3.0-10ug/ml.