2.1. Materials

Pea seeds (Pisum sativum L., cultivar Navarro) were provided by Norddeutsche Pflanzenzucht Hans-Georg-Lembke KG (Holtsee, Germany). Trypsin and Esperase^® 8.0 L were obtained from Sigma-Aldrich (Munich, Germany). Papain was from Carl Roth GmbH (Karlsruhe, Germany). L. plantarum (DSM 20174) was purchased from the German collection of microorganisms and cell cultures (Deutsche Sammlung von Mikroorganismen und Zellkulturen, Germany). Broad Range™ Unstained Protein Standard, 4–20% Criterion™ TGX stain-free™ precast polyacrylamide gels, Coomassie Brilliant Blue R-250 were from Bio-Rad Laboratories GmbH (Feldkirchen, Germany). Sodium dihydrogen phosphate, sodium dodecyl sulfate, sodium tetraborate decahydrate, o-phthaldialdehyde, and sodium monohydrogen phosphate were purchased from Sigma-Aldrich (Munich, Germany). All chemicals used in this study were of analytical grade unless otherwise indicated.