Detection and quantitation of glutamate carboxypeptidase II in human blood. Issue 7 (20th March 2014)

• Record Type: Journal Article
• Authors: Knedlík, Tomáš; Navrátil, Václav; Vik, Viktor; Pacík, Dalibor; Šácha, Pavel; Konvalinka, Jan
• Is Part Of: Prostate. Volume 74:Issue 7(2014)
• Page Start: 768
• Page End: 780
• Publication Date: 2014-03-20
• Subjects: Prostate -- Diseases -- Periodicals; 616
• DOI: 10.1002/pros.22796
• Languages: English
• ISSNs: 0270-4137

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="pros22796-sec-0001" sec-type="section"> <title>BACKGROUND</title> <p>Glutamate carboxypeptidase II (GCPII) is a transmembrane enzyme that cleaves <italic>N</italic>‐acetyl‐<sc>L</sc>‐aspartyl‐<sc>L</sc>‐glutamate (NAAG) in the brain. GCPII is highly expressed in the prostate and prostate cancer and might be associated with prostate cancer progression. Another exopeptidase, plasma glutamate carboxypeptidase (PGCP), was reported to be similar to GCPII and to share its NAAG‐hydrolyzing activity.</p> </sec> <sec id="pros22796-sec-0002" sec-type="section"> <title>METHODS</title> <p>We performed a radioenzymatic assay with [<sup>3</sup>H]NAAG as a substrate to detect and quantify the enzymatic activity of GCPII in plasma. Using a specific antibody raised against native GCPII (2G7), we immunoprecipitated GCPII from human plasma. We also cloned two PGCP constructs, expressed them in insect cells, and tested them for their NAAG‐hydrolyzing activity.</p> </sec> <sec id="pros22796-sec-0003" sec-type="section"> <title>RESULTS</title> <p>We detected GCPII protein in human plasma and found that its concentration ranges between 1.3 and 17.2 ng/ml in volunteers not diagnosed with prostate cancer. Recombinant PGCP was enzymatically active but exhibited no NAAG‐hydrolyzing activity.</p> </sec> <sec id="pros22796-sec-0004" sec-type="section"> <title>CONCLUSION</title> <p>GCPII is present in human blood, and its concentration within a healthy population varies. Recombinant PGCP does not hydrolyze NAAG, suggesting that GCPII alone is responsible for the NAAG‐hydrolyzing activity observed in human blood. The potential correlation between GCPII serum levels and the disease status of prostate cancer patients will be further investigated. <italic>Prostate 74:768–780, 2014</italic>. © 2014 Wiley Periodicals, Inc.</p> </sec> </abstract>