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Pijning T, Vujičić‐Žagar A, van der Laan J, de Jong RM, Ramirez‐Palacios C, Vente A, Edens L, Dijkstra BW. Structural and time-resolved mechanistic investigations of protein hydrolysis by the acidic proline-specific endoprotease from Aspergillus niger. Protein Sci 2024; 33:e4856. [PMID: 38059672 PMCID: PMC10731622 DOI: 10.1002/pro.4856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/16/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023]
Abstract
Proline-specific endoproteases have been successfully used in, for example, the in-situ degradation of gluten, the hydrolysis of bitter peptides, the reduction of haze during beer production, and the generation of peptides for mass spectroscopy and proteomics applications. Here we present the crystal structure of the extracellular proline-specific endoprotease from Aspergillus niger (AnPEP), a member of the S28 peptidase family with rarely observed true proline-specific endoprotease activity. Family S28 proteases have a conventional Ser-Asp-His catalytic triad, but their oxyanion-stabilizing hole shows a glutamic acid, an amino acid not previously observed in this role. Since these enzymes have an acidic pH optimum, the presence of a glutamic acid in the oxyanion hole may confine their activity to an acidic pH. Yet, considering the presence of the conventional catalytic triad, it is remarkable that the A. niger enzyme remains active down to pH 1.5. The determination of the primary cleavage site of cytochrome c along with molecular dynamics-assisted docking studies indicate that the active site pocket of AnPEP can accommodate a reverse turn of approximately 12 amino acids with proline at the S1 specificity pocket. Comparison with the structures of two S28-proline-specific exopeptidases reveals not only a more spacious active site cavity but also the absence of any putative binding sites for amino- and carboxyl-terminal residues as observed in the exopeptidases, explaining AnPEP's observed endoprotease activity.
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Affiliation(s)
- Tjaard Pijning
- Biomolecular X‐ray Crystallography, Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of GroningenGroningenThe Netherlands
| | - Andreja Vujičić‐Žagar
- Biomolecular X‐ray Crystallography, Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of GroningenGroningenThe Netherlands
| | | | | | | | - Andre Vente
- Taste, Texture and HealthDSM‐FirmenichDelftThe Netherlands
| | - Luppo Edens
- Taste, Texture and HealthDSM‐FirmenichDelftThe Netherlands
| | - Bauke W. Dijkstra
- Biomolecular X‐ray Crystallography, Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of GroningenGroningenThe Netherlands
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Akeroyd M, van Zandycke S, den Hartog J, Mutsaers J, Edens L, van den Berg M, Christis C. AN-PEP, Proline-Specific Endopeptidase, Degrades All Known Immunostimulatory Gluten Peptides in Beer Made from Barley Malt. Journal of the American Society of Brewing Chemists 2018. [DOI: 10.1094/asbcj-2016-2300-01] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | | | | | | | - Luppo Edens
- DSM Biotechnology Center, Delft, The Netherlands
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Salden BN, Montserrat V, Troost FJ, Bruins MJ, Edens L, Bartholomé R, Haenen GR, Winkens B, Koning F, Masclee AA. Letter: gluten digestion in the stomach and duodenum by Aspergillus niger-derived enzyme - things to ponder. Authors' reply. Aliment Pharmacol Ther 2015; 42:946-7. [PMID: 26331568 DOI: 10.1111/apt.13382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Affiliation(s)
- B N Salden
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, NUTRIM, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands.
| | - V Montserrat
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - F J Troost
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, NUTRIM, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - M J Bruins
- DSM Biotechnology Centre, Delft, The Netherlands
| | - L Edens
- DSM Biotechnology Centre, Delft, The Netherlands
| | - R Bartholomé
- Department of Pharmacology and Toxicology, CARIM, Maastricht University, Maastricht, The Netherlands
| | - G R Haenen
- Department of Pharmacology and Toxicology, CARIM, Maastricht University, Maastricht, The Netherlands
| | - B Winkens
- Department of Methodology and Statistics, CAPHRI, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - F Koning
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - A A Masclee
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, NUTRIM, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
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Salden BN, Monserrat V, Troost FJ, Bruins MJ, Edens L, Bartholomé R, Haenen GR, Winkens B, Koning F, Masclee AA. Editorial: enhancing gluten digestion in the stomach - a further help to minimise unintentional ingestion? Authors' reply. Aliment Pharmacol Ther 2015; 42:485. [PMID: 26179761 DOI: 10.1111/apt.13296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Affiliation(s)
- B N Salden
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, NUTRIM, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands.
| | - V Monserrat
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - F J Troost
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, NUTRIM, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - M J Bruins
- DSM Biotechnology Centre, Delft, The Netherlands
| | - L Edens
- DSM Biotechnology Centre, Delft, The Netherlands
| | - R Bartholomé
- Department of Pharmacology and Toxicology, CARIM, Maastricht University, Maastricht, The Netherlands
| | - G R Haenen
- Department of Pharmacology and Toxicology, CARIM, Maastricht University, Maastricht, The Netherlands
| | - B Winkens
- Department of Methodology and Statistics, CAPHRI, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - F Koning
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - A A Masclee
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, NUTRIM, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
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Salden BN, Monserrat V, Troost FJ, Bruins MJ, Edens L, Bartholomé R, Haenen GR, Winkens B, Koning F, Masclee AA. Randomised clinical study: Aspergillus niger-derived enzyme digests gluten in the stomach of healthy volunteers. Aliment Pharmacol Ther 2015; 42:273-85. [PMID: 26040627 PMCID: PMC5032996 DOI: 10.1111/apt.13266] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/31/2015] [Accepted: 05/13/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Aspergillus niger prolyl endoprotease (AN-PEP) efficiently degrades gluten molecules into non-immunogenic peptides in vitro. AIM To assess the efficacy of AN-PEP on gluten degradation in a low and high calorie meal in healthy subjects. METHODS In this randomised, double-blind, placebo-controlled, cross-over study 12 healthy volunteers attended to four test days. A liquid low or high calorie meal (4 g gluten) with AN-PEP or placebo was administered into the stomach. Via a triple-lumen catheter gastric and duodenal aspirates were sampled, and polyethylene glycol (PEG)-3350 was continuously infused. Acetaminophen in the meals tracked gastric emptying time. Gastric and duodenal samples were used to calculate 240-min area under the curve (AUC0-240 min ) of ?-gliadin concentrations. Absolute ?-gliadin AUC0-240 min was calculated using duodenal PEG-3350 concentrations. RESULTS AN-PEP lowered α-gliadin concentration AUC0-240 min, compared to placebo, from low and high calorie meals in stomach (low: 35 vs. 389 μg × min/mL; high: 53 vs. 386 μg × min/mL; P < 0.001) and duodenum (low: 7 vs. 168 μg × min/mL; high: 4 vs. 32 μg × min/mL; P < 0.001) and absolute α-gliadin AUC0-240 min in the duodenum from low (2813 vs. 31 952 μg × min; P < 0.001) and high (2553 vs. 13 095 μg × min; P = 0.013) calorie meals. In the placebo group, the high compared to low calorie meal slowed gastric emptying and lowered the duodenal α-gliadin concentration AUC0-240 min (32 vs. 168 μg × min/mL; P = 0.001). CONCLUSIONS AN-PEP significantly enhanced gluten digestion in the stomach of healthy volunteers. Increasing caloric density prolonged gastric residence time of the meal. Since AN-PEP already degraded most gluten from low calorie meals, no incremental effect was observed by increasing meal caloric density. ClinicalTrials.gov, Number: NCT01335503; www.trialregister.nl, Number: NTR2780.
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Affiliation(s)
- B. N. Salden
- Division of Gastroenterology‐HepatologyDepartment of Internal MedicineNUTRIMMaastricht University Medical Center (MUMC+)MaastrichtThe Netherlands
| | - V. Monserrat
- Department of Immunohematology and Blood TransfusionLeiden University Medical Centre (LUMC)LeidenThe Netherlands
| | - F. J. Troost
- Division of Gastroenterology‐HepatologyDepartment of Internal MedicineNUTRIMMaastricht University Medical Center (MUMC+)MaastrichtThe Netherlands
| | | | - L. Edens
- DSM Biotechnology CentreDelftThe Netherlands
| | - R. Bartholomé
- Department of Pharmacology and ToxicologyCARIMMaastricht UniversityMaastrichtThe Netherlands
| | - G. R. Haenen
- Department of Pharmacology and ToxicologyCARIMMaastricht UniversityMaastrichtThe Netherlands
| | - B. Winkens
- Department of Methodology and StatisticsCAPHRIMaastricht University Medical Center (MUMC+)MaastrichtThe Netherlands
| | - F. Koning
- Department of Immunohematology and Blood TransfusionLeiden University Medical Centre (LUMC)LeidenThe Netherlands
| | - A. A. Masclee
- Division of Gastroenterology‐HepatologyDepartment of Internal MedicineNUTRIMMaastricht University Medical Center (MUMC+)MaastrichtThe Netherlands
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Janssen G, Christis C, Kooy-Winkelaar Y, Edens L, Smith D, van Veelen P, Koning F. Ineffective degradation of immunogenic gluten epitopes by currently available digestive enzyme supplements. PLoS One 2015; 10:e0128065. [PMID: 26030273 PMCID: PMC4452362 DOI: 10.1371/journal.pone.0128065] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/23/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Due to the high proline content of gluten molecules, gastrointestinal proteases are unable to fully degrade them leaving large proline-rich gluten fragments intact, including an immunogenic 33-mer from α-gliadin and a 26-mer from γ-gliadin. These latter peptides can trigger pro-inflammatory T cell responses resulting in tissue remodeling, malnutrition and a variety of other complications. A strict lifelong gluten-free diet is currently the only available treatment to cope with gluten intolerance. Post-proline cutting enzymes have been shown to effectively degrade the immunogenic gluten peptides and have been proposed as oral supplements. Several existing digestive enzyme supplements also claim to aid in gluten degradation. Here we investigate the effectiveness of such existing enzyme supplements in comparison with a well characterized post-proline cutting enzyme, Prolyl EndoPeptidase from Aspergillus niger (AN-PEP). METHODS Five commercially available digestive enzyme supplements along with purified digestive enzymes were subjected to 1) enzyme assays and 2) mass spectrometric identification. Gluten epitope degradation was monitored by 1) R5 ELISA, 2) mass spectrometric analysis of the degradation products and 3) T cell proliferation assays. FINDINGS The digestive enzyme supplements showed comparable proteolytic activities with near neutral pH optima and modest gluten detoxification properties as determined by ELISA. Mass spectrometric analysis revealed the presence of many different enzymes including amylases and a variety of different proteases with aminopeptidase and carboxypeptidase activity. The enzyme supplements leave the nine immunogenic epitopes of the 26-mer and 33-mer gliadin fragments largely intact. In contrast, the pure enzyme AN-PEP effectively degraded all nine epitopes in the pH range of the stomach at much lower dose. T cell proliferation assays confirmed the mass spectrometric data. CONCLUSION Currently available digestive enzyme supplements are ineffective in degrading immunogenic gluten epitopes.
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Affiliation(s)
- George Janssen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, The Netherlands
| | | | - Yvonne Kooy-Winkelaar
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, The Netherlands
| | - Luppo Edens
- DSM Food Specialties, Delft, The Netherlands
| | - Drew Smith
- DSM Food Specialties, South Bend, United States of America
| | - Peter van Veelen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, The Netherlands
| | - Frits Koning
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, The Netherlands
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Shi J, de Roos A, Schouten O, Zheng C, Vink C, Vonk B, Kliphuis A, Schaap A, Edens L. Properties of Hemoglobin Decolorized with a Histidine-Specific Protease. J Food Sci 2015; 80:E1202-8. [PMID: 25924935 DOI: 10.1111/1750-3841.12809] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 12/24/2014] [Indexed: 12/01/2022]
Affiliation(s)
- Jing Shi
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
| | - Andre de Roos
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
| | - Olaf Schouten
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
| | - Chaoya Zheng
- Darling Ingredients Intl; Kanaaldijk Noord 20-21 5691NM Son the Netherlands
| | - Collin Vink
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
| | - Brenda Vonk
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
| | - Annette Kliphuis
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
| | - Albert Schaap
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
| | - Luppo Edens
- DSM Food Specialties; Alexander Fleminglaan 1 2613AX Delft the Netherlands
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Tack GJ, van de Water JMW, Bruins MJ, Kooy-Winkelaar EMC, van Bergen J, Bonnet P, Vreugdenhil ACE, Korponay-Szabo I, Edens L, von Blomberg BME, Schreurs MWJ, Mulder CJ, Koning F. Consumption of gluten with gluten-degrading enzyme by celiac patients: A pilot-study. World J Gastroenterol 2013; 19:5837-47. [PMID: 24124328 PMCID: PMC3793137 DOI: 10.3748/wjg.v19.i35.5837] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 10/05/2012] [Accepted: 10/30/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To assesses the safety and efficacy of Aspergillus niger prolyl endoprotease (AN-PEP) to mitigate the immunogenic effects of gluten in celiac patients.
METHODS: Patients with initial diagnosis of celiac disease as confirmed by positive serology with subtotal or total villous atrophy on duodenal biopsies who adhere to a strict gluten-free diet (GFD) resulting in normalised antibodies and mucosal healing classified as Marsh 0 or I were included. In a randomised double-blind placebo-controlled pilot study, patients consumed toast (approximately 7 g/d gluten) with AN-PEP for 2 wk (safety phase). After a 2-wk washout period with adherence of the usual GFD, 14 patients were randomised to gluten intake with either AN-PEP or placebo for 2 wk (efficacy phase). Measurements at baseline included complaints, quality-of-life, serum antibodies, immunophenotyping of T-cells and duodenal mucosa immunohistology. Furthermore, serum and quality of life questionnaires were collected during and after the safety, washout and efficacy phase. Duodenal biopsies were collected after the safety phase and after the efficacy phase. A change in histological evaluation according to the modified Marsh classification was the primary endpoint.
RESULTS: In total, 16 adults were enrolled in the study. No serious adverse events occurred during the trial and no patients withdrew during the trial. The mean score for the gastrointestinal subcategory of the celiac disease quality (CDQ) was relatively high throughout the study, indicating that AN-PEP was well tolerated. In the efficacy phase, the CDQ scores of patients consuming gluten with placebo or gluten with AN-PEP did not significantly deteriorate and moreover no differences between the groups were observed. During the efficacy phase, neither the placebo nor the AN-PEP group developed significant antibody titers. The IgA-EM concentrations remained negative in both groups. Two patients were excluded from entering the efficacy phase as their mucosa showed an increase of two Marsh steps after the safety phase, yet with undetectable serum antibodies, while 14 patients were considered histologically stable on gluten with AN-PEP. Also after the efficacy phase, no significant deterioration was observed regarding immunohistological and flow cytometric evaluation in the group consuming placebo compared to the group receiving AN-PEP. Furthermore, IgA-tTG deposit staining increased after 2 wk of gluten compared to baseline in four out of seven patients on placebo. In the seven patients receiving AN-PEP, one patient showed increased and one showed decreased IgA-tTG deposits.
CONCLUSION: AN-PEP appears to be well tolerated. However, the primary endpoint was not met due to lack of clinical deterioration upon placebo, impeding an effect of AN-PEP.
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Luoto S, Jiang Z, Brinck O, Sontag-Strohm T, Kanerva P, Bruins M, Edens L, Salovaara H, Loponen J. Malt hydrolysates for gluten-free applications: Autolytic and proline endopeptidase assisted removal of prolamins from wheat, barley and rye. J Cereal Sci 2012. [DOI: 10.1016/j.jcs.2012.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Geraedts MCP, Troost FJ, Fischer MAJG, Edens L, Saris WHM. Direct induction of CCK and GLP-1 release from murine endocrine cells by intact dietary proteins. Mol Nutr Food Res 2011; 55:476-84. [PMID: 20938986 DOI: 10.1002/mnfr.201000142] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 08/11/2010] [Accepted: 08/26/2010] [Indexed: 11/08/2022]
Abstract
SCOPE Consumption of high-protein diets cause elevated levels of CCK and GLP-1. Although unknown, this might be due to protein breakdown by various proteases that originate from the gastrointestinal tract. This study investigated which dietary proteins, hydrolysates, or synthetic-peptides are most potent to affect secretion of CCK and GLP-1 in STC-1 cells known for satiety hormone release. METHODS AND RESULTS Addition of intact proteins to STC-1 cells exerted strong effects on secretion of satiety hormones. Casein, whey, and pea showed strongest effects on CCK release, whereas casein, codfish, egg, and wheat showed most pronounced effects on GLP-1 release. Egg-hydrolysate stimulated release of CCK and GLP-1, whereas all other tested hydrolysates and synthetic-peptides showed no significant effects on hormone release. Addition of a combination of trypsin and casein-hydrolysate, codfish, egg, egg-hydrolysate, sodium-casein, wheat-hydrolysate, or wheat resulted in additional stimulation of CCK release, compared to only the protein. Addition of a combination of DPP-IV and egg-hydrolysate, ovomucoid, or sodium-casein decreased GLP-1 levels. CONCLUSION This study showed that specific intact, or partially digested proteins, in contrast to protein-hydrolysates and synthetic-peptides, stimulated hormone release. We conclude that intact proteins exert strong effects on satiety hormone release, and may therefore provide potent dietary supplements for prevention or treatment of obesity.
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Affiliation(s)
- Maartje C P Geraedts
- Department of Human Biology, Maastricht University Medical Centre+, Maastricht, The Netherlands.
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Mitea C, Havenaar R, Drijfhout JW, Edens L, Dekking L, Koning F. Efficient degradation of gluten by a prolyl endoprotease in a gastrointestinal model: implications for coeliac disease. Gut 2008; 57:25-32. [PMID: 17494108 DOI: 10.1136/gut.2006.111609] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Coeliac disease is caused by an immune response to gluten. As gluten proteins are proline rich they are resistant to enzymatic digestion in the gastrointestinal tract, a property that probably contributes to the immunogenic nature of gluten. AIMS This study determined the efficiency of gluten degradation by a post-proline cutting enzyme, Aspergillus niger prolyl endoprotease (AN-PEP), in a dynamic system that closely mimics the human gastrointestinal tract (TIM system). METHODS Two experiments were performed. In the first, a slice of bread was processed in the TIM system with and without co-administration of AN-PEP. In the second, a standard fast food menu was used. Samples of the digesting meals were taken from the stomach, duodenum, jejunum and ileum compartments at time zero until 4 hours after the start of the experiment. In these samples the levels of immunogenic peptides from gliadins and glutenins were assessed by monoclonal antibody-based competition assays, Western blot analysis and proliferation T-cell assays. RESULTS AN-PEP accelerated the degradation of gluten in the stomach compartment to such an extent that hardly any gluten reached the duodenum compartment. CONCLUSION AN-PEP is capable of accelerating the degradation of gluten in a gastrointestinal system that closely mimics in-vivo digestion. This implies that the co-administration of AN-PEP with a gluten-containing meal might eliminate gluten toxicity, thus offering patients the possibility of abandoning (occasionally) their strict gluten-free diet.
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Affiliation(s)
- C Mitea
- Department of Immunohematology and Blood Transfusion, E3-Q, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
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Stepniak D, Spaenij-Dekking L, Mitea C, Moester M, de Ru A, Baak-Pablo R, van Veelen P, Edens L, Koning F. Highly efficient gluten degradation with a newly identified prolyl endoprotease: implications for celiac disease. Am J Physiol Gastrointest Liver Physiol 2006; 291:G621-9. [PMID: 16690904 DOI: 10.1152/ajpgi.00034.2006] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Celiac disease is a T cell-driven intolerance to wheat gluten. The gluten-derived T cell epitopes are proline-rich and thereby highly resistant to proteolytic degradation within the gastrointestinal tract. Oral supplementation with prolyl oligopeptidases has therefore been proposed as a potential therapeutic approach. The enzymes studied, however, have limitations as they are irreversibly inactivated by pepsin and acidic pH, both present in the stomach. As a consequence, these enzymes will fail to degrade gluten before it reaches the small intestine, the site where gluten induces inflammatory T cell responses that lead to celiac disease. We have now determined the usefulness of a newly identified prolyl endoprotease from Aspergillus niger for this purpose. Gluten and its peptic/tryptic digest were treated with prolyl endoprotease, and the destruction of the T cell epitopes was tested using mass spectrometry, T cell proliferation assays, ELISA, reverse-phase HPLC, SDS-PAGE, and Western blotting. We observed that the A. niger prolyl endoprotease works optimally at 4-5 pH, remains stable at 2 pH, and is completely resistant to digestion with pepsin. Moreover, the A. niger-derived enzyme efficiently degraded all tested T cell stimulatory peptides as well as intact gluten molecules. On average, the endoprotease from A. niger degraded gluten peptides 60 times faster than a prolyl oligopeptidase. Together these results indicate that the enzyme from A. niger efficiently degrades gluten proteins. Future studies are required to determine if the prolyl endoprotease can be used as an oral supplement to reduce gluten intake in patients.
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Affiliation(s)
- Dariusz Stepniak
- Dept. of Immunohematology and Blood Transfusion, Leiden Univ. Medical Center, P.O. BOX 9600, 2300 RC Leiden, The Netherlands
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Lopez M, Edens L. Effective prevention of chill-haze in beer using an acid proline-specific endoprotease from Aspergillus niger. J Agric Food Chem 2005; 53:7944-9. [PMID: 16190654 DOI: 10.1021/jf0506535] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Chill-haze formation during beer production is known to involve polyphenols that interact with proline-rich proteins. We hypothesized that incubating beer wort with a proline-specific protease would extensively hydrolyze these proline-rich proteins, yielding a peptide fraction that is unable to form a haze. Predigestion of the proline-rich wheat gliadin with different proteases pointed toward a strong haze-suppressing effect by a proline-specific enzyme. This finding was confirmed in small-scale brewing experiments using a recently identified proline-specific protease with an acidic pH optimum. Subsequent pilot plant trials demonstrated that, upon its addition during the fermentation phase of beer brewing, even low levels of this acidic enzyme effectively prevented chill-haze formation in bottled beer. Results of beer foam stability measurements indicated that the enzyme treatment leaves the beer foam almost unaffected. In combination with the enzyme's cost-effectiveness and regulatory status, these preliminary test results seem to favor further industrial development of this enzymatic beer stabilization method.
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Affiliation(s)
- Michel Lopez
- DSM Food Specialties, Post Office Box 1, 2600 MA Delft, The Netherlands
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Edens L, Dekker P, van der Hoeven R, Deen F, de Roos A, Floris R. Extracellular prolyl endoprotease from Aspergillus niger and its use in the debittering of protein hydrolysates. J Agric Food Chem 2005; 53:7950-7. [PMID: 16190655 DOI: 10.1021/jf050652c] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The observation that the bitterest peptides from casein hydrolysates contain several proline residues led us to hypothesize that a proline-specific protease would be instrumental in debittering such peptides. To identify the desired proline-specific activity, a microbiological screening was carried out in which the chromogenic peptide benzyloxycarbonyl-glycine-proline-p-nitroanilide (Z-Gly-Pro-pNA) was used as the substrate. An Aspergillus niger (A. niger) strain was identified that produces an extracellular proline-specific protease with an acidic pH optimum. On the basis of sequence similarities, we conclude that the A. niger-derived enzyme probably belongs to the S28 family of clan SC of serine proteases rather than the S9 family to which prolyl oligopeptidases belong. Incubating the overexpressed and purified enzyme with bitter casein hydrolysates showed a major debittering effect. Reversed phase HPLC analysis revealed that this debittering effect is accompanied by a significant reduction of the number of hydrophobic peptides present.
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Affiliation(s)
- Luppo Edens
- DSM Food Specialties, Post Office Box 1, 2600 MA Delft, The Netherlands.
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15
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Abstract
This study was conducted to develop an equation for the prediction of outcome in neonatal foals undergoing treatment in an intensive care unit (ICU). Fifty-three physical examination, historical, and clinicopathologic variables were analyzed from the records of 99 neonatal foals (< 14 days of age) treated in the neonatal ICU of the Equine Medical Center. The outcome was recorded and the results were categorized into either surviving or nonsurviving groups. The mean values for the 2 groups were compared, and variables that differed significantly between the two groups were retained and used to construct a logistic regression equation. Retained variables were heart rate, temperature, and neutrophil count. The predictive equation then was tested prospectively in 2 additional groups of foals from 2 separate ICUs. The predicted outcome was compared to the actual outcome, and performance variables were calculated. Sensitivity (.83), specificity (.87), negative predictive value (.72), and positive predictive value (.93) were determined for foals from one neonatal ICU; the sensitivity (.83), specificity (.44), negative predictive value (.44), and positive predictive value (.83) were lower for foals at a second, separate ICU.
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Affiliation(s)
- M Furr
- Marion duPont Scott Equine Medical Center, Virginia-Maryland Regional College of Veterinary Medicine, Leesburg 22075, USA
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Abstract
A 5-year-old Thoroughbred mare presented with a 4 week history of weight loss, fever and leukopenia. Rectally, a large active foetus, thickened spleen and an abdominal mass were palpated. Leukopenia, mild anaemia, marked thrombocytopenia and hyperfibrinogenaemia were found. Cytology and cytochemical staining of a bone marrow aspirate supported a diagnosis of acute myelogenous leukaemia. The mare deteriorated despite medical therapy and was humanely euthanased.
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Affiliation(s)
- N C Ringger
- Department of Large Animal Clinical Sciences, University of Florida, Gainesville 32610, USA
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Ledeboer AM, Edens L, Maat J, Visser C, Bos JW, Verrips CT, Janowicz Z, Eckart M, Roggenkamp R, Hollenberg CP. Molecular cloning and characterization of a gene coding for methanol oxidase in Hansenula polymorpha. Nucleic Acids Res 1985; 13:3063-82. [PMID: 2582370 PMCID: PMC341221 DOI: 10.1093/nar/13.9.3063] [Citation(s) in RCA: 152] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The structural gene and the regulatory DNA sequence of the yeast Hansenula polymorpha methanol oxidase have been isolated. According to the nucleotide sequence data obtained, the structural gene encodes a 664 amino acids long protein, contains no intervening sequences, and the 5'- and 3'-non-coding region contains several sequences implicated in transcription initiation and termination in the yeast Saccharomyces cerevisiae. Although the methanol oxidase is translocated to the peroxisomes, no cleavable signal sequence was found at the N-terminus of the protein.
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Abstract
Various maturation forms of the plant protein thaumatin were expressed in yeast, using a promoter fragment of the glyceraldehyde- 3P -dehydrogenase (GAPDH) gene. Plasmids encoding preprothaumatin were shown to direct the synthesis of a processed form of the plant protein. The important role of signal sequences in the expression of the plant protein in yeast was indicated by the observation that plasmids encoding processed thaumatin forms were only poorly expressed, if at all. Nucleotide sequence analysis of the 843 nucleotide GAPDH promoter fragment revealed a characteristic structure with two regions of dyad symmetry containing translational starts of GAPDH and a putative 38 amino acid peptide. A promoter fragment from which the upstream region was deleted proved to be less efficient in thaumatin expression.
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Edens L, Heslinga L, Klok R, Ledeboer AM, Maat J, Toonen MY, Visser C, Verrips CT. Cloning of cDNA encoding the sweet-tasting plant protein thaumatin and its expression in Escherichia coli. Gene X 1982; 18:1-12. [PMID: 7049841 DOI: 10.1016/0378-1119(82)90050-6] [Citation(s) in RCA: 186] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The structural gene of the sweet-tasting plant protein (prepro)thaumatin was cloned and expressed in Escherichia coli. Expression was effected under control of lac and trp promoter/operator systems and through the use of bacterial ribosome-binding sites. The naturally occurring thaumatin II represents a processed form. The primary translation product, preprothaumatin, of the cloned mRNA-derived cDNA contains extensions at both the amino terminus and the carboxy terminus. The amino terminal extension of 22 amino acids is hydrophobic and very much resembles an excretion-related signal sequence. The six amino acids-long carboxy terminal extension is very acidic in character, in contrast to the overall highly basic thaumatin molecule. The possible role of such an acidic tail with respect to compartmentalization is discussed.
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Edens L, Heslinga L, Klok R, Ledeboer AM, Maat J, Toonen M, Visser C, Verrips CT. Expression of cDNA encoding the sweet plant protein thaumatin in E. coli. Antonie Van Leeuwenhoek 1982. [DOI: 10.1007/bf00400393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Edens L, Konings RN, Schoenmakers JG. Transcription of bacteriophage M13 DNA: existence of promoters directly preceding genes III, VI, and I. J Virol 1978; 28:835-42. [PMID: 731795 PMCID: PMC525808 DOI: 10.1128/jvi.28.3.835-842.1978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In vitro transcription and coupled transcription-translation studies have been performed with restriction fragments of bacteriophage M13 replicative-form DNA which contain either gene III, gene VI, or gene I. It could be demonstrated that DNA fragments which contain gene III were able to direct the synthesis of gene III protein. Fragments which encompassed genes VI and I gave rise to the synthesis of gene I protein only, whereas gene I-containing fragments were able to direct the synthesis of gene I protein. None of the fragments studied gave rise to a detectable level of gene VI protein, although an RNA transcript of gene VI could readily be obtained during in vitro transcription of the relevant gene VI-containing DNA fragments. From these results we have concluded that the promoters A0.44 and A0.49 are located in front of genes VI and I, respectively, and that gene III is also equipped with a promoter (X0.25). Introduction of a single cleavage within the gene III region does not abolish the expression of genes VI and I in vitro. Hence, the expression of these genes is not solely dependent on the initiation of RNA synthesis at the gene III promoter or on leakage of transcription through the central termination site (T0.25), but is also determined by the initiation frequency of RNA synthesis at their individual promoters.
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Abstract
With the aid of transcription studies on restriction fragments of bacteriophage M13 DNA it has been demonstrated that at least eight promoter sites are located on the M13 genome. Five of these promoters initiate the synthesis of RNA chains which contain at their 5'-terminal end pppG (G promoters), while the other three promoters initiate RNA chains which start exclusively with pppA (A promoters). The positions of these promoter sites on the physical map are: 0.82 (G0.82), 0.88 (G0.88), 0.94 (G0.94), 0.01 (G0.01), 0.08 (G0.08), 0.36 (A0.36), 0.51 (A0.51) and 0.56 (A0.56). The G promoters were found to be clustered within a distance of one-third of the genome length from the central termination site for transcription (map position 0.77). The A promoters, however, were found at greater distances from this termination signal. Based upon the incorporation of [gamma-32P]ATP or [gamma-32P]GTP, the capacity of these promoters to initiate the synthesis of RNA chains varies. The strongest G promoters are G0.82, G0.94 and G0.08 and the strongest A promoter is A0.36. As judged from their position on the genetic map, it is postulated that two promoters, namely G0.94 and G0.01, are located within gene II. The other promoters are most probably located immediately in front of the gene VIII/VII boundary (G0.82), and immediately in front of gene V (G0.88), gene II (G0.08), gene IV (A0.36), gene I (A0.51) and gene VI (A0.56). No evidence has been obtained so far for the existence of a promoter immediately in front of gene III.
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Edens L, Konings RN, Schoenmakers JG. Physical mapping of the central terminator for transcription on the bacteriophage M13 genome. Nucleic Acids Res 1975; 2:1811-20. [PMID: 1103087 PMCID: PMC343549 DOI: 10.1093/nar/2.10.1811] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
With the aid of in vitro transcription and translation studies it has been demonstrated that termination of transcription on bacteriophage M13 replicative form DNA occurs at a unique site which is located immediately distal to the 3'-end of gene VIII, the gene which codes for the major capsid protein. The position of this site has been mapped accurately on the enzyme cleavage maps by transcription of restriction fragments of M13 RF DNA. The central termination site was found to be located in restriction fragment Hap-B2 at 450 nucleotides from the 5'-end of its viral strand (0.77 fractional length clockwise from the unique Hind II enzyme cleavage site).
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