title: Production and characterization of two major Aspergillus oryzae secreted prolyl endopeptidases able to efficiently digest proline-rich peptides of gliadin.
abstract: Prolyl endopeptidases are key enzymes in the digestion of proline-rich proteins. Fungal extracts rich in prolyl endopeptidases produced by a species such as Aspergillus oryzae used in food fermentation would be of particular interest for the development of an oral enzyme therapy product in patients affected by intolerance to gluten. Two major A. oryzae secreted prolyl endopeptidases of the MEROPS S28 peptidase family, AoS28A and AoS28B, were identified when this fungus was grown at acidic pH in a medium containing soy meal protein or wheat gliadin as the sole source of nitrogen. AoS28B was produced by 12 reference A. oryzae strains used in food fermentation. AoS28A was secreted by six of these 12 strains. This protease is the orthologue of the previously characterized Aspergillus fumigatus (AfuS28) and Aspergillus niger (AN-PEP) prolyl endopeptidases which are encoded by genes with a similar intron-exon structure. Large amounts of secreted AoS28A and AoS28B were obtained by gene overexpression in A. oryzae. AoS28A and AoS28B are endoproteases able to cleave N-terminally blocked proline substrates. Both enzymes very efficiently digested the proline-rich 33-mer of gliadin, the most representative immunotoxic peptide deriving from gliadin, with some differences in terms of specificity and optimal pH. Digestion of the gliadin peptide in short peptides with both enzymes was found to occur from its N terminus.
authors.affiliation: 1​ Laboratoire des Catecholamines et Peptides, Service de Biomédecine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Philippe J
authors.initials: PJ
authors.lastname: Eugster
authors.affiliation: 2​ Service de Dermatologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Karine
authors.initials: K
authors.lastname: Salamin
authors.affiliation: 1​ Laboratoire des Catecholamines et Peptides, Service de Biomédecine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Eric
authors.initials: E
authors.lastname: Grouzmann
authors.affiliation: 2​ Service de Dermatologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Monod
mesh_terms: D001236:Aspergillus oryzae / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D055162:Biocatalysis; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005903:Gliadin / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D011392:Proline / Q000378:metabolism*; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D005656:Fungal Proteins; D010455:Peptides; D005903:Gliadin; D011392:Proline; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases