Complement factor D (EC 3.4.21.46) (Adipsin) (C3 convertase activator) (Properdin factor D)
1_MHSWE 6_ RLAVL 11_ VLLGA 16_ AACAA 21_ PPRGR 26_ ILGGR 31_ EAEAH 36_ ARPYM 41_ ASVQL 46_ NGAHL 51_ CGGVL 56_ VAEQW 61_ VLSAA 66_ HCLED 71_ AADGK 76_ VQVLL 81_ GAHSL 86_ SQPEP 91_ SKRLY 96_ DVLRA 101_ VPHPD 106_ SQPDT 111_ IDHDL 116_ LLLQL 121_ SEKAT 126_ LGPAV 131_ RPLPW 136_ QRVDR 141_ DVAPG 146_ TLCDV 151_ AGWGI 156_ VNHAG 161_ RRPDS 166_ LQHVL 171_ LPVLD 176_ RATCN 181_ RRTHH 186_ DGAIT 191_ ERLMC 196_ AESNR 201_ RDSCK 206_ GDSGG 211_ PLVCG 216_ GVLEG 221_ VVTSG 226_ SRVCG 231_ NRKKP 236_ GIYTR 241_ VASYA 246_AWIDS
1: Serine protease that initiates the alternative pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system (PubMed:21205667, PubMed:22362762, PubMed:6769474, PubMed:874324, PubMed:9748277). In contrast to other complement pathways (classical, lectin and GZMK) that are directly activated by pathogens or antigen-antibody complexes, the alternative complement pathway is initiated by the spontaneous hydrolysis of complement C3 (PubMed:21205667, PubMed:22362762, PubMed:6769474, PubMed:874324). The alternative complement pathway acts as an amplification loop that enhances complement activation by mediating the formation of C3 and C5 convertases (PubMed:21205667, PubMed:22362762, PubMed:6769474, PubMed:874324). Activated CFD cleaves factor B (CFB) when the latter is complexed with complement C3b, activating the C3 convertase of the alternative pathway (PubMed:21205667, PubMed:6769474, PubMed:874324, PubMed:9748277)