Compstatin is a complement inhibitor which can bind C3 inhibiting proteolytic cleavage by C3 convertase with IC50 value of 28 μM and activate classical and alternative complement pathways with IC50 values of 63 and 12 μM, respectively.
The complement system is a key part of the innate and adaptive immune system and plays a major role in homeostasis by clearing altered host cells and invading pathogens. Compstatin, a 13-residue peptide, is an effective inhibitor of the activation of complement component C3 with IC50 value of 12 μM and thus blocks a central and crucial step in the complement cascade[1]. In vitro studies of compstatin in human blood indicated that a major pathway of biotransformation was the removal of Ile1, which could be blocked by N-acetylation of the peptide[2]. Subsequent interaction analysis confirmed that compstatin binds NHP C3 (baboon) and human C3 with similar affinity, but it does not bind to mouse or rat C3[3]. Compstatin produced complete inhibition at a total dose of 21 mg/kg when given as a combination of bolus injection and infusion. It completely inhibited in vivo heparin/protamine-induced complement activation without adverse effects on heart rate or systemic arterial, central venous, and pulmonary arterial pressures[4].
作用机制
The crystal structure reveals that the compstatin-binding site is formed by the macroglobulin (MG) domains 4 and 5[1].
Compstatin/坎普他汀 细胞研究
细胞系
浓度
检测类型
检测时间
活性说明
数据源
RPE cells
50 uM
Function assay
Inhibition of complement activation in human fetal RPE cells assessed as reduction in C5b-9 formation at 50 uM by fluorescence assay in presence of complement-competant human serum
Inhibition of complement activation in human fetal RPE cells assessed as reduction in C5b-9 formation at 50 uM by fluorescence assay in presence of complement-competant human serum
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