title: Identification of a novel complex between human kallikrein 2 and protease inhibitor-6 in prostate cancer tissue.
abstract: Human kallikrein (hK) 2 is an arginine-selective serine protease expressed predominantly in the prostate that has an 80% sequence identity with prostate-specific antigen. Expression of hK2 is elevated in the tumor epithelium compared to benign prostate tissue. We have purified, sequenced, and identified a novel hK2 complex in prostate tissue consisting of hK2 and a serine protease inhibitor known as protease inhibitor-6 (PI-6). This 64-kDa SDS-PAGE stable complex is elevated in the tumor and is approximately 10% of total hK2. No comparable complex of prostate-specific antigen was detected. PI-6, also known as cytoplasmic antiprotease, has been characterized as an intracellular inhibitor of trypsin and chymotrypsin-like proteases, which has high homology to plasminogen activator inhibitor 1 and 2. The physiological role of PI-6 in the prostate and its relationship to hK2 and prostate cancer are under investigation.
authors.affiliation: Hybritech Inc., San Diego, California 92121, USA. sdmikolajczyk@beckman.com
authors.forename: S D
authors.initials: SD
authors.lastname: Mikolajczyk
authors.forename: L S
authors.initials: LS
authors.lastname: Millar
authors.forename: K M
authors.initials: KM
authors.lastname: Marker
authors.forename: H G
authors.initials: HG
authors.lastname: Rittenhouse
authors.forename: R L
authors.initials: RL
authors.lastname: Wolfert
authors.forename: L S
authors.initials: LS
authors.lastname: Marks
authors.forename: M C
authors.initials: MC
authors.lastname: Charlesworth
authors.forename: D J
authors.initials: DJ
authors.lastname: Tindall
mesh_terms: D014408:Biomarkers, Tumor; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D007610:Kallikreins / Q000378:metabolism*; D008297:Male; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D011485:Protein Binding; D015842:Serine Proteinase Inhibitors / Q000378:metabolism; D015843:Serpins / Q000378:metabolism*; D020840:Tissue Kallikreins
chemical_list: D014408:Biomarkers, Tumor; D015842:Serine Proteinase Inhibitors; D015843:Serpins; C094472:serpin B6; D007610:Kallikreins; D020840:Tissue Kallikreins