Peptidomics of casein digestion in the pig duodenum
Data accompanied with the paper "Digestion of micellar casein in duodenum cannulated pigs. Correlation between in vitro simulated gastric digestion and in vivo data" Food Chemistry vol. 343, 128424 (2021). The data are generated through the analysis of the duodenal content of six pigs fed milk casein. Samples after 5, 10, 15, 20, 30, 45, 60, 120 and 150 min of intake were analyzed by liquid chromatography coupled to tandem mass spectrometry after normalization of the protein content. A list of peptide sequences derived from milk caseins with indication of parent protein, subject number, time of digestion, position range in the mature protein and sequence in one-letter code is provided.
Steps to reproduce
Large White pigs were surgically fitted with a T-shaped cannula in the duodenum (10 cm downstream from the pylorus). Test meal (casein powder reconstituted in water 5% (w/v) was provided to the pigs for 10min. The animals had no access to water neither 1h before nor 7h after the meal delivery. Duodenum effluents were collected 15min before and 5, 10, 15, 20, 30, 45, 60, 90, 120 and 150 min after ingestion of test meal in plastic bottles. The sampling was ended when 40ml were pooled or after 3 min of sampling time. Pefabloc®, (Sigma-Aldrich, St. Louis, MO, USA) at 2.5 mM final concentration was added to the collecting containers. Peptide sequencing was conducted by HPLC-MS/MS (ion trap) by matching with the main genetic variants from the milk caseins. Freeze-dried digests were reconstituted in solvent A (water:formic acid, 100:0.1, v/v) and centrifuged at 13000 × g, 10 min. 50 µL of supernatant was injected for each sample. HPLC-MS/MS was carried out using an Agilent 1100 HPLC system (Agilent Technologies, Waldbron, Germany), with a Mediterranea Sea C18 column (150 × 2.1 mm, Teknokroma, Barcelona, Spain) connected to an Esquire 3000 linear ion trap mass spectrometer (Bruker Daltonics GmbH, Bremen, Germany) fitted with an electrospray ionization source. For peptide elution, the flow was set at 0.2 mL/min and a linear gradient over 120 min from 0 to 45% of solvent B (acetonitrile:formic acid, 100:0.1, v/v) was employed. The mass/charge (m/z) ranged from 100 to 1200 and the target mass was set at 900 m/z. Data were processed by using Data Analysis (version 4.0, Bruker DaltonicsGmbH, Bremen, Germany). Peptide sequencing was performed using the MASCOT v2.4 protein search engine (Matrix Science). Regardless of its P value, a manual revision was done for each identification peptide spectrum.