Evaluation of solid-phase extraction procedures in peptide analysis

Tryptophan-containing milk protein-derived dipeptides inhibit xanthine oxidase

“…The activated carbon was washed with water to remove any unbound material. Peptides were then eluted stepwise using 10, 20, 30, 40, 50, 60, 70 and 100 % (v/v) ACN as described by Herraiz and Casal [41]. The different fractions were dried using a solvent evaporator (Genevac, EZ-2 Plus, Genevac Ltd., Ipswich, UK).…”

“…Elution from activated carbon with ethanol has been carried out after extraction of peptides from a casein hydrolyzate [1]. In our study, different acetonitrile concentrations were used to elute peptides adsorbed on the activated carbon as described previously with different commercial SPE cartridges by Herraiz and Casal [41]. The 9 fractions eluted from the activated carbon cartridge, including the unbound fraction, were all assayed at 1.25 mg mL -1 for XO inhibitory activity (Table 4).…”

Milk protein hydrolysates activate 5-HT2C serotonin receptors: influence of the starting substrate and isolation of bioactive fractions

“…49 The SPE cartridge was connected to a manifold (Phenomenex, Cheshire, UK) to extract the different fractions under vacuum (15 70 mmHg). The procedure followed with the SPE cartridge was a modification of the fractionation technique described by Herraiz et al 50 A volume of 30 mL NaCNH-240 min filtrate was slowly applied at the top of the SPE cartridge to allow adsorption of the peptides. The SPE cartridge was washed with water to remove 75 any unbound material.…”

“…[9][10][11][12][13][14][15][16][17][18][19][20] Currently, the only FDA-approved 45 drug in the treatment of obesity is the over-the-counter available oral lipase inhibitor, orlistat (Xenical ®; FDA approved 2007), albeit it is not as effective as other drugs in reducing body weight. Changes in diet, exercise and the pharmaceutical approach only allow short term reduction of body weight which generally does 50 not last beyond a year often due to non-compliance of overweight people. 1 Weight loss strategies aimed at dietary alterations are still preferred over pharmacotherapies and are a lower risk alternative to bariatric procedures.…”

“…Hydrolysates arising from different casein-derived substrates were evaluated in vitro for their agonist properties towards 5-HT 2C serotonin receptors. Different 50 fractionation protocols were applied to a bioactive sodium caseinate hydrolysate (NaCNH-240 min) in order to selectively separate bioactive peptides from inactive peptides. Fractionation was carried out based on molecular mass, hydrophobicity or isolectric point differences with the view to better understanding 55 the physicochemical properties of the bioactive peptides therein.…”