Purity > 90% as determined by SDS-PAGE. MW: 11kDa. Full Length of Mature Protein: 26-102aa. N-terminal 6xHis-tagged. Homo sapiens (Human). Potent inhibitor of the complent mbrane attack complex (MAC) action. Acts by binding to the C8 and/or C9 complents of the assbling MAC, thereby preventing incorporation of the multiple copies of C9 required for complete formation of the osmolytic pore. This inhibitor appears to be species-specific. Involved in signal transduction for T-cell activation complexed to a protein tyrosine kinase.The soluble form from urine retains its specific complent binding activity, but exhibits greatly reduced ability to inhibit MAC assbly on cell mbranes.