Detection and quantitation of glutamate carboxypeptidase II in human blood
Article first published online: 20 MAR 2014
© 2014 Wiley Periodicals, Inc.
Volume 74, Issue 7, pages 768–780, May 2014
How to Cite
Knedlík, T., Navrátil, V., Vik, V., Pacík, D., Šácha, P. and Konvalinka, J. (2014), Detection and quantitation of glutamate carboxypeptidase II in human blood. Prostate, 74: 768–780. doi: 10.1002/pros.22796
- Issue published online: 15 APR 2014
- Article first published online: 20 MAR 2014
- Manuscript Accepted: 10 FEB 2014
- Manuscript Received: 19 DEC 2013
- Grant Agency of the Czech Republic. Grant Number: P304-12-0847
- OPPK project. Grant Number: CZ.2.16/3.1.00/24016
- glutamate carboxypeptidase II;
- prostate-specific membrane antigen;
- serum marker;
- prostate cancer;
- plasma glutamate carboxypeptidase
Glutamate carboxypeptidase II (GCPII) is a transmembrane enzyme that cleaves N-acetyl-L-aspartyl-L-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.
We performed a radioenzymatic assay with [3H]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.
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.
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. Prostate 74:768–780, 2014. © 2014 Wiley Periodicals, Inc.