title: Peptidases specific for proline-containing peptides and their unusual peptide-dependent regulation in Oenococcus oeni.
abstract: OBJECTIVE
  Growth of the lactic acid bacterium (LAB) Oenococcus oeni, which is involved in malolactic fermentation during the winemaking process, is stimulated by peptides originating from yeast. In this study, we investigated the impact of peptides on O. oeni growth, peptidase activity and the expression of genes encoding the studied peptidases.
  
  
  RESULTS
  Low levels of PepN activity and very high levels of PepI activity were observed in O. oeni, whereas levels of PepX activity were intermediate. The level of biosynthesis of these O. oeni peptidases was shown to depend on peptides present in the culture medium. These results were confirmed by transcriptional analyses of putative pep genes. The mechanism of repression by peptides did not involve a CodY-like regulator.
  
  
  CONCLUSIONS
  Peptides from yeast decrease the levels of enzymatic activity and relative gene expression of O. oeni peptidases. Peptidases specific for proline-containing peptides are important for O. oeni nitrogen metabolism.
  
  
  CONCLUSIONS
  We report here for the first time that the enzymes involved in the assimilation of proline-containing peptides by O. oeni differ from the well-described proteolytic system of milk LAB. This may reflect a specific adaptation to the wine environment.
authors.affiliation: Laboratoire de Recherche en Vigne et Vin, Institut Universitaire de la Vigne et du Vin Jules Guyot, Université de Bourgogne, Dijon, France.
authors.forename: J-F
authors.initials: JF
authors.lastname: Ritt
authors.forename: F
authors.initials: F
authors.lastname: Remize
authors.forename: C
authors.initials: C
authors.lastname: Grandvalet
authors.forename: J
authors.initials: J
authors.lastname: Guzzo
authors.forename: D
authors.initials: D
authors.lastname: Atlan
authors.forename: H
authors.initials: H
authors.lastname: Alexandre
mesh_terms: D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D009584:Nitrogen / Q000378:metabolism; D056585:Oenococcus / Q000201:enzymology* / Q000235:genetics; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D010447:Peptide Hydrolases; D009584:Nitrogen