Human plasma kallikrein, a serine protease, is first synthesized as an inactive plasma prekallikrein in liver and circulates in the plasma. Once activated by activated coagulation factor XII (FXIIa), plasma kallikrein releases bradykinin (an inflammatory mediator) from high molecular weight kininogen (HMWK). Plasma kallikrein is involved in several physiological and pathological processes such as blood coagulation, the classical complement cascade pathway and the activation of the alternative complement pathway. Plasma kallikrein also plays a role in the induction of elastase release from neutrophils and conversion of prourokinase to urokinase in fibrinolysis.
The SensoLyte®Rh110 Plasma Kallikrein Activity Assay Kit employs a fluorescent peptide substrate for the detection of enzyme activity. This substrate contains rodamine 110 fluorophore (Rh110). Plasma kallikrein cleaves this Rh110 substrate and results in the release of a bright green fluorescence and can be detected at excitation/emission=490 nm/520 nm. The longer wavelength spectra and higher extinction coefficient of Rh110 provide greater sensitivity and less interference from other reaction components. This assay can detect as low as 1 ng/mL active plasma kallikrein. This kit could be used to detect enzyme activity in purified enzyme preparations, biological samples and it can also be applied for compound screening.