Bradykinin is an alias for the gene, Kininogen 1, in humans. Other names include: Kininogen-1; Alpha-2-thiol proteinase inhibitor; Fitzgerald factor; High molecular weight kininogen; HMWK; Williams-Fitzgerald-Flaujeac factor; bradykinin; BDK; BK; KNG. The encoded protein has an amino acid length of 644 and a mass of 72.0 kDa. Other isoforms may exist. This gene shares homology with other species, including: Frog.