Complement factor I is a member of the peptidase S1 family present in the blood plasma. Factor I is an 88kD protein consisting of one polypeptide chain of 35.4kD and one of 27.6kD. Factor I is a serine protease which inactivates complement components C3b and C4b. C3b cleavage requires the presence of cofactors complement component (3b/4b) receptor 1 (CR1), membrane cofactor protein or factor H, while C4b cleavage requires complement component 4 binding protein or CR1. Factor I has no natural inhibitors. Dysfunctional factor I can lead to uncontrolled activation of the alternative complement pathway causing in systemic depletion of C3 and lower levels of factors B and H, resulting in recurrent pyogenic infections. Defects in CFI are also associated with hemolytic uremic syndrome. Applications: Suitable for use in Flow Cytometry, ELISA, Functional Assays, Immunohistochemistry and Western Blot. Other applications not tested. Recommended Dilution: ELISA: 1:500-1:4000 Immunohistochemistry: frozen sections Optimal dilutions to be determined by the researcher. Recommended IHC Positive Control: Kidney from post streptoccal glomerulonephritis patients Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
