Tags: Protein.
Complement decay-accelerating factor also known as CD55 or DAF is a protein that in humans is encoded by the CD55 gene.Decay accelerating factor is a 70 kDa membrane protein that regulates the complement system on the cell surface. DAF recognizes C4b and C3b fragments that are created during C4 (classical complement pathway and lectin pathway) and C3 (alternate complement pathway) activation.