Hydrolases;
Acting on peptide bonds (peptidases);
Serine endopeptidases
Reaction(IUBMB)
Selective cleavage of some Arg! and Lys! bonds, including Lys!Arg and Arg!Ser in (human) kininogen to release bradykinin
Comment
Formed from plasma prokallikrein (Fletcher factor) by factor XIIa. Activates coagulation factors XII, VII and plasminogen. Selective for Arg > Lys in P1, in small molecule substrates.
History
EC 3.4.21.34 created 1965 as EC 3.4.4.21, transferred 1972 to EC 3.4.21.8, part transferred 1981 to EC 3.4.21.34
Mapping the active sites of bovine thrombin, factor IXa, factor Xa, factor XIa, factor XIIa, plasma kallikrein, and trypsin with amino acid and peptide thioesters: development of new sensitive substrates.