Purity ~90% (SDS-PAGE). Type IV collagen is the major structural component of glomerular basent membranes (GBM), forming a 'chicken-wire' meshwork together with laminins, proteoglycans and entactin/nidogen. Tumstatin, a cleavage fragment corresponding to the collagen alpha 3(IV) NC1 domain, possesses both anti-angiogenic and anti-tumor cell activity; these two anti-tumor properties may be regulated via RGD-independent ITGB3-mediated mechanisms. Source: Recombinant protein corresponding to aa1446-1667 from human COL4A3, fused to His-Tag at N-terminal, expressed in E. coli. Molecular Weight: ~28.5kD AA