Properdin is a protein that in humans is encoded by the CFP (complement factor properdin) gene. Properdin is plasma glycoprotein that activates the complement system of the innate immune system.

Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases.

Properdin is a component of alternative complement pathway that protects C3b from catalysis by complement regulator FH and FI and promotes stabilization of C3 convertase. In properdin KO mice, a high fat diet led to increased body weight, fat mass and plasma leptin levels, and delayed postprandial TG clearance.

Key to the effects of the alternative pathway is properdin, a serum glycoprotein that can both initiate and positively regulate alternative pathway activity. Properdin is produced by many different leukocyte subsets and circulates as cyclic oligomers of monomeric subunits.

Properdin deficiency is a rare X-linked disease in which properdin, an important complement factor responsible for the stabilization of the alternative C3 convertase, is deficient. [1]

Properdin released from activated neutrophils binds to “dangerous self” (apoptotic cells) and “dangerous non-self” (microbial pathogens), marking them for complement activation and phagocytosis.

Jan 15, 2008 · Properdin is a positive regulator of alternative pathway (AP) complement. The current understanding of properdin function is that it facilitates AP complement activation by stabilizing the C3 convertase C3bBb.

The Properdin System and Immunity: I. Demonstration and Isolation of a New Serum Protein, Properdin, and Its Role in Immune Phenomena. Science 120, 279-285 (1954). DOI:10.1126/science.120.3112.279

Properdin is a soluble glycoprotein which has a unique role as a positive regulator of the alternative complement pathway by binding and stabilizing the inherently labile C3/C5 convertase enzymes, C3bBb and C3bBbC3b, substantially increasing their half-lives .

Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases.