title: Application of in-gel protease assay in a biological sample: characterization and identification of urokinase-type plasminogen activator (uPA) in secreted proteins from a prostate cancer cell line PC-3.
abstract: A considerable problem in proteomics is to separate and identify functional proteins that participate in specific biological processes. To expedite the analysis of active proteases, we have developed a substrate-specific, sensitive in-gel trypsin activity assay after two-dimensional (2-D) separation in a sodium dodecyl sulphate (SDS)-polyacrylamide gel [22]. Using this method, we detected and characterized Arg-specific protease activity in the secreted protein sample of a prostate cancer cell line, PC-3, in 1-D and 2-D gels. Mass spectrometry (MS) identified the protease as urokinase-type plasminogen activator (uPA). Western blotting using anti-uPA antibody and protease inhibition tests confirmed the identification. Since no antibody was involved in the procedure, the result clearly demonstrates the feasibility of this method for identifying novel proteases in biological samples.
authors.affiliation: Oncology Research Centre, Prince of Wales Hospital, Randwick, NSW, Australia.
authors.forename: Zhenjun
authors.initials: Z
authors.lastname: Zhao
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Raftery
authors.forename: Xiao Mei
authors.initials: XM
authors.lastname: Niu
authors.forename: Merilla M
authors.initials: MM
authors.lastname: Daja
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Russell
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D013379:Substrate Specificity; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis*
chemical_list: D009363:Neoplasm Proteins; D010447:Peptide Hydrolases; D014568:Urokinase-Type Plasminogen Activator