Semenogelins I and II bind zinc and regulate the activity of prostate-specific antigen

In semen, the gel proteins SgI and SgII (semenogelins I and II) are digested by PSA (prostate-specific antigen), resulting in liquefaction and release of motile spermatozoa. Semen contains a high concentration of Zn2+, which is known to inhibit the protease activity of PSA. We characterized the binding of Zn2+ to SgI and SgII and found evidence that these proteins are involved in regulating the activity of PSA. Intact SgI and SgII and synthetic semenogelin peptides were used in the experiments. Binding of Zn2+ was studied by radioligand blotting, titration with a zinc (II) fluorophore chelator and NMR analysis. A chromogenic substrate was used to measure the enzymatic activity of PSA. SgI and SgII bound Zn2+ with a stoichiometry of at least 10 mol (mol of protein)−1 and with an average dissociation constant of approx. 5 μM per site. Moreover, Zn2+-inhibited PSA was activated by exposure to SgI or SgII. Since both proteins have high affinity for Zn2+ and are the dominating proteins in semen, they probably represent the major Zn2+ binders in semen, one function of which may be to regulate the activity of PSA. The system is self-regulating, and PSA is maintained in an active state by its substrate.

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High-Affinity Peptide Ligands to Prostate-Specific Antigen Identified by Polysome Selection

Biochemical and Biophysical Research Communications ◽

10.1006/bbrc.1997.6331 ◽

1997 ◽

Vol 232 (2) ◽

pp. 578-582 ◽

Cited By ~ 43

Author(s):

Geoffrey M. Gersuk ◽

Michael J. Corey ◽

Eva Corey ◽

James E. Stray ◽

Glenn H. Kawasaki ◽

...

Keyword(s):

Prostate Specific Antigen ◽

Specific Antigen ◽

Peptide Ligands ◽

High Affinity ◽

Affinity Peptide

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Presence and enzymatic activity of prostate-specific antigen in archival prostate cancer samples

Oncology Reports ◽

10.3892/or_00000089 ◽

1994 ◽

Vol 20 (4) ◽

Author(s):

Duivenvoorden

Keyword(s):

Prostate Cancer ◽

Enzymatic Activity ◽

Prostate Specific Antigen ◽

Specific Antigen

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Enzymatic activity of free-prostate-specific antigen (f-PSA) is not required for some of its physiological activities

The Prostate ◽

10.1002/pros.21385 ◽

2011 ◽

Vol 71 (15) ◽

pp. 1680-1690 ◽

Cited By ~ 6

Author(s):

Kailash C. Chadha ◽

Bindukumar B. Nair ◽

Srikant Chakravarthi ◽

Rita Zhou ◽

Alejandro Godoy ◽

...

Keyword(s):

Enzymatic Activity ◽

Prostate Specific Antigen ◽

Specific Antigen

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Purification and characterization of different molecular forms of prostate-specific antigen in human seminal fluid

Clinical Chemistry ◽

10.1093/clinchem/41.11.1567 ◽

1995 ◽

Vol 41 (11) ◽

pp. 1567-1573 ◽

Cited By ~ 118

Author(s):

W M Zhang ◽

J Leinonen ◽

N Kalkkinen ◽

B Dowell ◽

U H Stenman

Keyword(s):

Enzymatic Activity ◽

Prostate Specific Antigen ◽

Seminal Fluid ◽

Specific Antigen ◽

Anion Exchange Chromatography ◽

Exchange Chromatography ◽

Terminal Sequence ◽

Amino Terminal ◽

Intact Psa ◽

Amino Terminal Sequence

Abstract We have developed a new procedure for purifying prostate-specific antigen (PSA) from human seminal fluid. The method is based on ammonium sulfate precipitation, hydrophobic interaction chromatography, gel filtration, and anion-exchange chromatography. It can be completed within 2 days with a recovery of intact PSA of 30%. By anion-exchange chromatography, five isoforms of PSA (A, B, C, D, and E) can be separated. The major form (PSA-B) consists of the intact enzyme, as shown by the occurrence of only one band of 33 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing or nonreducing conditions, and by amino acid sequencing, which reveals only one amino-terminal sequence corresponding to the reported amino-terminal sequence of intact PSA. The specific absorbance of 1 g/L PSA-B at 280 nm was 1.61, and 80% of the PSA-B formed a complex with alpha 1-antichymotrypsin, indicating that it is enzymatically active. Three cleaved forms of PSA with different nicking sites and low enzymatic activity were separated from intact PSA by ion-exchange chromatography. In addition, we isolated a glycosylation variant, PSA-A, which showed a higher isoelectric point (pI = 7.2) than PSA-B (pI = 6.9) but similar enzymatic activity; this form accounts for 5-10% of total PSA. After treatment with sialidase, PSA-A and B had the same isoelectric point value (pI = 7.7).

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Inhibition of the enzymatic activity of prostate-specific antigen by boric acid and 3-nitrophenyl boronic acid

The Prostate ◽

10.1002/pros.10166 ◽

2002 ◽

Vol 54 (1) ◽

pp. 44-49 ◽

Cited By ~ 39

Author(s):

Maria T. Gallardo-Williams ◽

Robert R. Maronpot ◽

Robert N. Wine ◽

Susan H. Brunssen ◽

Robert E. Chapin

Keyword(s):

Enzymatic Activity ◽

Boric Acid ◽

Prostate Specific Antigen ◽

Boronic Acid ◽

Specific Antigen

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Prostate-specific antigen: characterization of epitopes by synthetic peptide mapping and inhibition studies

Clinical Chemistry ◽

10.1093/clinchem/43.4.575 ◽

1997 ◽

Vol 43 (4) ◽

pp. 575-584 ◽

Cited By ~ 16

Author(s):

Eva Corey ◽

Sandra K Wegner ◽

Michael J Corey ◽

Robert L Vessella

Keyword(s):

Enzymatic Activity ◽

Prostate Specific Antigen ◽

Conformational Changes ◽

Polyclonal Antibody ◽

Peptide Mapping ◽

Specific Antigen ◽

Free Psa ◽

Linear Epitopes ◽

Inhibition Studies ◽

Antigenic Regions

Abstract To improve our understanding of the prostate-specific antigen (PSA) antigenic regions, we studied the association targets of one anti-PSA polyclonal antibody and 10 anti-PSA monoclonal antibodies (mAbs). We also examined the ability of the mAbs to inhibit PSA enzymatic activity and block the association of PSA with α1-antichymotrypsin (ACT). Linear epitope mapping with a polyclonal antibody indicated the presence of six major antigenic regions in PSA. Examination of the panel of mAbs established that three of them bind to linear epitopes. Five of the mAbs inhibited >90% of PSA enzymatic activity. However, inhibition of PSA enzymatic activity and hindrance of PSA-ACT association by mAbs cannot be used to predict whether the mAbs bind to free PSA, the PSA-ACT complex, or both. Some of the mAbs may block PSA-ACT association through peripheral occlusion of the binding site, or through induction of conformational changes in PSA.

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Prevalence and Factors Associated with High Concentration of Prostate-Specific Antigen: ELSIA Study

Biology ◽

10.3390/biology9100329 ◽

2020 ◽

Vol 9 (10) ◽

pp. 329

Author(s):

Lucas Lima Galvão ◽

Sheilla Tribess ◽

Tamara Guimarães Silva ◽

Cremilda Garcia Santa Rosa ◽

Cristian Gomes Pereira ◽

...

Keyword(s):

Prostate Cancer ◽

Blood Pressure ◽

Prostate Specific Antigen ◽

Metabolic Diseases ◽

Specific Antigen ◽

The Elderly ◽

Cross Sectional Study ◽

High Concentration ◽

Cross Sectional ◽

Factors Associated

Background: Prostate cancer (PC) is the second most common cancer among men, behind only non-melanoma skin cancer, and the main method of screening for PC is the prostate-specific antigen (PSA). To analyze the prevalence and the factors associated with high concentration of PSA in the elderly is essential to understand this outcome, and building strategies to decrease their rates of morbidity and mortality. Methods: We performed a cross-sectional study with 96 elderly men. A high level of PSA was defined by >4.0 ng/mL. In order to identify sociodemographic, health, functional and behavioral variables, which may be associated with high levels of PSA, we carried out a multivariate analysis using Poisson regression. Results: The prevalence of high levels of PSA was 21.9% (n = 21). High levels of PSA was associated with years of study, race/ethnicity and family arrangement, health perception, systolic blood pressure, diastolic blood pressure, metabolic diseases, alcohol consumption and sedentary behavior. Conclusions: The study found a high prevalence of high PSA concentrations in the elderly and several aspects are associated, which can be a worrying factor for their health, since PSA is an important marker of prostate cancer.

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Anti-Free Prostate-specific Antigen Monoclonal Antibody Epitopes Defined by Mimotopes and Molecular Modeling

Clinical Chemistry ◽

10.1093/clinchem/45.5.638 ◽

1999 ◽

Vol 45 (5) ◽

pp. 638-650 ◽

Cited By ~ 22

Author(s):

Sandrine Michel ◽

Gilbert Deléage ◽

Jean-Philippe Charrier ◽

Jacques Passagot ◽

Nicole Battail-Poirot ◽

...

Keyword(s):

Prostate Cancer ◽

Molecular Modeling ◽

Enzymatic Activity ◽

Prostate Specific Antigen ◽

Specific Antigen ◽

Free Psa ◽

Total Psa ◽

Sandwich Assays ◽

Antibody Epitopes

Abstract Background: Prostate-specific antigen (PSA) is an important marker for the diagnosis and management of prostate cancer, and the free PSA/total PSA ratio has been shown to be efficient for distinguishing prostate cancer from benign prostatic hyperplasia. We report here the characterization of seven mouse monoclonal antibodies (mAbs) and the partial localization of two conformational epitopes identified by anti-free PSA mAbs. Methods: The mAbs were studied by competition and sandwich assays, and the epitope localization of the two anti-free PSA mAbs (6C8D8 and 5D3D11) was performed using phage displayed peptide libraries and molecular modeling. Results: The seven mAbs were classified into three groups according to their recognition specificities and their ability to inhibit the enzymatic activity of PSA and the formation of PSA-α1-antichymotrypsin (ACT) complex. Among the anti-free PSA mAb group, 6C8D8 recognized the phage displayed peptide RKLRPHWLHFHPVAV, two parts of which presented similarities with two regions distant on the PSA sequence but joined in the tridimensional structure. mAb 5D3D11 recognized the peptide DTPYPWGWLLDEGYD, which is similar to a PSA region located on the board of the groove containing the PSA enzymatic site. Both epitopes were located in the theoretical ACT binding site described previously. Moreover, these mAbs were able to inhibit the enzymatic activity of PSA. Conclusions: These epitope localizations are in agreement with the ability of both mAbs to inhibit enzymatic activity and ACT fixation. The results presented here could bring information for the generation of clinically relevant PSA assays.

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