The cleavage specificity of the aspartic protease of cocoa beans involved in the generation of the cocoa-specific aroma precursors.
Particular peptides generated from the vicilin-class(7S) globulin of the cocoa beans by acid-induced proteolysis during cocoa fermentation are essential precursors of the cocoa-specific aroma notes. As revealed by in vitro studies, the formation of the cocoa-specific aroma precursors depends on the particular cleavage specificity of the cocoa aspartic protease, which cannot be substituted by pepsin. Therefore, we have investigated the effects of aspartic protease inhibitors on both enzymes and comparatively studied their cleavage specificities using different protein substrates and MALDI-TOF mass spectrometric analyses of the generated oligopeptides. Three classes of cleavage sites have been identified and characterized: (I) sequences exclusively cleaved by the cocoa enzyme, (II) sequences cleaved by both pepsin and the cocoa enzyme, and (III) those cleaved exclusively by pepsin. In contrast to most aspartic proteases from other origins, basic amino acid residues, particularly lysine, were found to be abundant in the specific cleavage sites of the cocoa enzyme.
Institute of Biochemistry, Charité - University Medicine Berlin, Charité-Platz 1/Virchowweg 6, D-10117 Berlin, Germany.
Katharina
K
Janek
Institute of Biochemistry, Charité - University Medicine Berlin, Charité-Platz 1/Virchowweg 6, D-10117 Berlin, Germany.
Agathe
A
Niewienda
Chair of General Microbiology and Microbial Genetics, Institute of Microbiology, Friedrich-Schiller-University Jena, Neugasse 24, D-07743 Jena, Germany.
Johannes
J
Wöstemeyer
Chair of General Microbiology and Microbial Genetics, Institute of Microbiology, Friedrich-Schiller-University Jena, Neugasse 24, D-07743 Jena, Germany. Electronic address: juergen.voigt@uni-jena.de.
Jürgen
J
Voigt
D000595:Amino Acid Sequence; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D057055:Aspartic Acid Proteases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002099:Cacao / Q000737:chemistry* / Q000201:enzymology* / Q000235:genetics; D000069956:Chocolate; D005285:Fermentation; D012639:Seeds / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D012903:Smell; D013552:Swine
D057055:Aspartic Acid Proteases; D016282:Aspartic Acid Endopeptidases
Aliskiren hemifumarate (PubChem CID: 6918427; Aroma precursors; Aspartic protease; Cleavage specificity; Cocoa beans; Pepsin; Pepstatin A (PubChem CID: 4742); Saquinavir (PubChem CID: 60787)