Factor D is a serine protease present in blood and tissue in an active sequence but self-inhibited conformation. The only known natural substrate of Factor D is Factor B, and cleavage of the Arg 234-Lys 235 scissile bond in Factor B results in two Factor B fragments, Ba and Bb.

Complement factor D, a serine protease of this pathway that is required for the formation of C3 convertase, is the rate-limiting enzyme. In this review, we discuss the function of factor D within the alternative pathway and its implication in both healthy physiology and disease.

Complement factor D (FD) is a serine protease that plays an essential role in the activation of the alternative pathway (AP) by cleaving complement factor B (FB) and generating the C3 convertases C3 (H 2 O)Bb and C3bBb. FD is produced mainly from adipose tissue and circulates in an activated form.

Factor D is the enzyme that activates factor B to form the C3 convertase of the alternative pathway. It is a serine protease of MW 24,000 that circulates in plasma in active form. The concentration of factor D in plasma is the lowest of all the complement proteins (1 µg/ml, Table II).

Factor D (FD) is an essential component of the complement alternative pathway (AP). It is an attractive pharmaceutical target because it is an AP-specific protease circulating in blood. Most components of the complement activation pathways are ...

Factor D is unique among serine proteases in that it requires neither enzymatic cleavage for expression of proteolytic activity nor inactivation by a serpin for its control. Regulation of factor D activity is instead attained by a novel mechanism ...

Factor D is a glycosylated protein composed of a single 24,000 Da polypeptide chain. It is an essential component of the alternative pathway of complement activation. Its only known function is to cleave and activate factor B when factor B is bound to C3b or a C3b-like protein such as C3(H 2 O) or CVF.

Oct 31, 2022 · Complement factor D (FD) is a serine protease that plays an essential role in the activation of the alternative pathway (AP) by cleaving complement factor B (FB) and generating the C3 convertases C3(H 2 O)Bb and C3bBb. FD is produced mainly from adipose tissue and circulates in an activated form.

Nov 5, 2020 · BCX9930 is a potent and selective orally bioavailable inhibitor of factor D in development for the treatment of PNH and other complement-mediated diseases.

Complement factor D, a serine protease of this pathway that is required for the formation of C3 convertase, is the rate-limiting enzyme. In this review, we discuss the function of factor D within the alternative pathway and its implication in both healthy physiology and disease.