Search Organism: All OrganismsArabidopsis thalianaBacillus subtilis 168Bos taurusCaenorhabditis elegansCanis familiarisDanio rerioDrosophila melanogasterEquus caballusEscherichia coli K12Gallus gallusHomo sapiensMacaca mulattaMus musculusNematostella vectensisOryza sativaPan troglodytesRattus norvegicusSaccharomyces cerevisiaeSchizosaccharomyces pombeStrongylocentrotus purpuratusTakifugu rubripesXenopus laevis home help / support contribute downloads mirrors about us Biochemistry Dec (2001); 40(50):15341-8 Characterization of hK4 (prostase), a prostate-specific serine protease: activation of the precursor of prostate specific antigen (pro-PSA) and single-chain urokinase-type plasminogen activator and degradation of prostatic acid phosphatase. Takayama TK, McMullen BA, Nelson PS, Matsumura M, Fujikawa K Departments of Biochemistry and Urology, University of Washington, Box 357350, Seattle, Washington 98195-7350, USA. tomt@u.washington.edu Abstract: hK4 (prostase, KLK4), a recently cloned prostate-specific serine protease and a member of the tissue kallikrein family, is a zymogen composed of 228 amino acid residues including an amino-terminal propiece, Ser-Cys-Ser-Gln-. A chimeric form of hK4 (ch-hK4) was constructed in which the propiece of hK4 was replaced by that of prostate-specific antigen (PSA) to create an activation site susceptible to trypsin-type proteases. ch-hK4 was expressed in Escherichia coli, isolated from inclusion bodies, refolded, and purified with an overall yield of 25%. The zymogen was readily self-activated during the refolding process to generate an active form (21 kDa) of hK4 (rhK4). rhK4 cleaved the chromogenic substrates Val-Leu-Arg-pNA (S-2266), Pro-Phe-Arg-pNA (S-2302), Ile-Glu-Gly-Arg-pNA (S-2222), and Val-Leu-Lys-pNA (S-2251), indicating that rhK4 has a trypsin-type substrate specificity. The rhK4 was inhibited by aprotinin (6 kDa), forming an equimolar 27 kDa complex. rhK4 readily activated both the precursor of PSA (pro-PSA) and single chain urokinase-type plasminogen activator (scuPA, pro-uPA). rhK4 also completely degraded prostatic acid phosphatase but failed to cleave serum albumin, another protein purified from human seminal plasma. These results indicate that hK4 may have a role in the physiologic processing of seminal plasma proteins such as pro-PSA, as well as in the pathogenesis of prostate cancer through its activation of pro-uPA. [PUBMED: 11735417] Copyright © 2009, Tyers Lab, The Samuel Lunenfeld Research Institute, Mount Sinai Hospital, All Rights Reserved. terms and conditions - privacy policy - Osprey Network Visualization System BioGRID: A General Repository for Interaction Datasets. Chris Stark, Bobby-Joe Breitkreutz, Teresa Reguly, Lorrie Boucher, Ashton Breitkreutz, Mike Tyers. Nucleic Acids Res. Jan 1;34:D535-9.