A activator for prekallikrein includes isolated, purified, or substantially purified
heat shock protein 90, a phosphate ion, and mixtures thereof. The prekallikrein
activator is part of an in vitro system for activating prekallikrein in the absence
of FXIIa. The system includes the activator, high-molecular weight kininogen, and
zinc ions. A method for activating prekallikrein to produce kallikrein in the absence
of FXIIa includes mixing prekallikrein with the activator and a composition comprising
high molecular weight kininogen and zinc ions. A method for evaluating the activity
of a test drug for the production of kallikrein comprises activating prekallikrein
and determining the kallikrein produced. The activity (promoting or inhibiting
ability) of the tested drug against the production of kallikrein in the absence
of FXIIa can be easily measured. The test drug may be an analgesic, anti-allergy,
anti-inflammatory drug.
