Factor B Protein

Purified human complement Factor B. Factor B is one of the proteins unique to the Alternative Complement Pathway. The 93 kD Factor B protein is made up of a single peptide chain. When the alternative pathway is activated either directly or by the classical pathway via the amplification loop, C3b can bind whole Factor B. Factor D can then cleave Factor B in a single site to yield Ba and Bb. Bb can then become the enzymatically active constituent of the C3 and C5 alternative pathway convertases.