title: ACE-inhibitory peptides from bovine caseins released with peptidases from Maclura pomifera latex.
abstract: In work reported here, a proteolytic extract prepared from Maclura pomifera latex was employed to hydrolyze bovine caseins. Densitograms of Tricine-sodium-dodecyl-sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) indicated that the caseins were considerably degraded after a 10-min reaction. The degree of hydrolysis determined by the 2,4,6-trinitrobenzenesulfonic-acid method was 17.1±0.7% after 180min of digestion. The concentration of small peptides increased with hydrolysis time, and analysis by reverse-phase high-performance liquid chromatography (RP HPLC) and mass spectrometry, revealed a virtually unchanged peptide profile. These results suggested that those proteases were highly specific, as only certain peptide bonds were cleaved. The hydrolysate of 180min displayed the highest inhibition of angiotensin-converting enzyme (ACE) showing an IC50of 1.72±0.25mg/mL, and the analysis of the peptide fractionation in this hydrolysate by RP HPLC exhibited two peaks responsible for that activity. Fragmentation analysis through the use of iterated matrix-assisted-laser-desorption-ionization-time-of-flight mass spectrometry (MALDI-TOF/TOF MS/MS) with the aid of bioinformatics tools enabled us to deduce two peptide sequences-one, YQEPVLGPVRGPFPIIV, having been previously reported as an ACE-inhibitor; the other, RFFVAPFPE, as yet undescribed. The presence of bioactive peptides in these casein hydrolysates argues for their potential use in the development of functional foods.
authors.affiliation: CIProVe, Faculty of Exact Sciences, National University of La Plata (UNLP), la Plata, Argentina. Electronic address: mariaaliciacorrons@hotmail.com.
authors.forename: María Alicia
authors.initials: MA
authors.lastname: Corrons
authors.affiliation: CIProVe, Faculty of Exact Sciences, National University of La Plata (UNLP), la Plata, Argentina. Electronic address: cliggieri@biol.unlp.edu.ar.
authors.forename: Constanza Silvina
authors.initials: CS
authors.lastname: Liggieri
authors.affiliation: Multidisciplinary Institute of Cellular Biology (IMBICE, CONICET-UNLP), La Plata, Argentina. Electronic address: sebatrejo@gmail.com.
authors.forename: Sebastián Alejandro
authors.initials: SA
authors.lastname: Trejo
authors.affiliation: CIProVe, Faculty of Exact Sciences, National University of La Plata (UNLP), la Plata, Argentina. Electronic address: brunomariela@biol.unlp.edu.ar.
authors.forename: Mariela Anahí
authors.initials: MA
authors.lastname: Bruno
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000818:Animals; D002364:Caseins / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D005591:Chemical Fractionation; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D031624:Maclura / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013379:Substrate Specificity
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D002364:Caseins; D010455:Peptides; D010447:Peptide Hydrolases
keywords: ACE-inhibitory peptide; Hydrolysate; Maclura pomifera; Plant peptidase