Role of hageman factor in the activation of guinea-pig pre-kallikrein.

Davies and Lowe (1963) showed that the 7 S y-globulin fraction of guinea-pig serum contained the enzyme kallikrein. The abilities of the y-globulin to increase vascular permeability and to hydrolyse esters of arginine and lysine appeared to be related properties, and both could be increased by shaking solutions of y-globulin with glass beads which had been treated with guinea-pig serum or by the addition of certain albumin-rich fractions obtained from guinea-pig serum. This activation led to the conclusion that the y-globulin fraction contained both active kallikrein and its precursor. This precursor has been referred to in the literature by a variety of names-for example, kallikreinogen, prokininogenase, pro-kallikrein. We propose to adhere to the Recommendations of the International Union of Biochemistry on Enzyme Nomenclature (1965) and refer to the precursor of kallikrein (E.C.3.4.4.21) as pre-kallikrein.