Quantitative proteomics and SWATH-MS to elucidate peri-receptor mechanisms in human salt taste sensitivity

• Published in: Food chemistry Vol. 254; pp. 95 - 102
• Main Authors: Stolle, Theresa, Grondinger, Freya, Dunkel, Andreas, Hofmann, Thomas
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.07.2018
• Subjects: Adult; Endopeptidase activity; Endopeptidases - metabolism; enzyme activity; Epithelial Sodium Channels - physiology; Female; Humans; Lipocalins - analysis; lysozyme; Male; mass spectrometry; Mass Spectrometry - methods; Muramidase - analysis; Oligopeptides - pharmacology; peptides; proteome; proteomics; Proteomics - methods; Saliva; Saliva - chemistry; Saliva - enzymology; Salt taste; Sensitivity; sensory evaluation; Sodium Chloride; Sodium Chloride, Dietary; stable isotopes; SWATH-MS; Targeted proteomics; Taste Perception - drug effects; Taste Perception - physiology; taste sensitivity; Taste Threshold - drug effects; Taste Threshold - physiology; trypsin; Trypsin - administration & dosage; Trypsin - metabolism; SWATH-MS; Sensitivity; Endopeptidase activity; Targeted proteomics; Saliva; Salt taste
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2018.01.160

•Lipocalin-1 and lysozyme C in saliva are indicative for NaCl insensitivity.•Endopeptidase enhances salty taste by releasing taste modulating peptides.•Peptide PLWR enhances salt taste above a threshold concentration of 6.5 μmol/L.•Oral peri-receptor events play a key role in human salt taste perception. Recently, studies on human salt taste sensitivity demonstrated that sodium chloride (NaCl) sensitive and non-sensitive subjects differed in their salivary proteome and, in particular, in endopeptidase activity. In order to investigate individual’s NaCl sensitivity and the role of endoprotease activity in salt taste perception, 20 panellists were classified according to NaCl sensitivity and saliva samples collected. A targeted protein quantitation by means of selected-reaction-monitoring (SRM) mass spectrometry and stable-isotope incorporation revealed the joint abundance of lysozyme C and lipocalin-1 to be indicative for non-sensitive subjects. Sensory studies performed after oral challenge with the serine-type endopeptidase trypsin demonstrated a salt enhancing effect which was assumed to be due to an in-vivo generation of salt-modulating peptides as shown by LC-SWATH-MS. Amongst those, the tetrapeptide PLWR was found to elicit salty taste enhancing activity above an extraordinarily low taste threshold concentration of 6.5 μmol/L.