Complement factor D (CFD) is also known as Adipsin, C3 convertase activator, Properdin factor D (PFD), which contains one peptidase S1 domain and belongs to the peptidase S1 family. CFD / Adipsin cleaves factor B when the latter is complexed with factor C3b, activating the C3bbb complex, which then becomes the C3 convertase of the alternate pathway. CFD / Adipsin is a serine protease that stimulates glucose transport for triglyceride accumulation in fats cells and inhibits lipolysis. Defects in CFD / Adipsin are the cause of complement factor D deficiency which predisposes to invasive meningococcal disease.