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αs2-casein f(203-208) [id=CAA0026]

Producer Organism : Native Protein : Production Method :
Sheep αs2-casein Enzymatic hydrolysis and Purification with LC method/Synthetic
Activity : Antibacterial
Target Organisms :

Gram-positive: Active against Listeria innocua CECT 910 T, Staphylococcus epidermidis CECT 231, Staphylococcus carnosus CECT 4491T at 0.5 mM.

Gram-negative: Active against Escherichia coli ATCC 25922 at 0.5 mM.

NOTE: No activity against Enterococcus faecalis CECT 795, Serratia marcescens CECT 854 at 0.5 mM .

Description :
Production method: Pepsin hydrolysis and purification with LC method/Synthetic.

Length : 6 Mass (Da): 810.01 Common Amino Acids : Y
Isolectric Point : 9.17 Net Charge : 1 Absent Amino Acids : ACDEFGHIKMNQSTW
Basic Residues : 1 Acidic Residues : 0 Hydrophobic Residues : 2
Polar Residues : 2 Boman Index : -6.24 Hydropathy Index : -0.117
Aliphatic Index : 113.33 Instability Index : 0 Extinction Coefficient : 2980
Absorbance 280nm : 596

Wheel representation

Hydrophobicity plot

Red solid plot : values according to the hydrophobicity scale of Kyte and Doolittle (reference paper).
Yellow dashed plot : Experimentally determined hydrophobicity scale for proteins at membrane interfaces(reference paper).
Green dotted-dashed plot : prediction of transmembrane helices (reference paper). In this scale (unlike the others), more negative values reflect greater hydrophobicity.

Citation: 1

Identification of antibacterial peptides from ovine alphas2-casein

Cited Entries: LFB0085, CAA0020, CAA0021, CAA0023, CAA0024, CAA0025, CAA0026

Authors:Lopez-Exposito, I., Gomez-Ruiz, J.A., Amigo, L., Recio, I.
Journal: International Dairy Journal 2006, 16(9).
CrossRef External Link
Abstract: The aim of this work was to isolate and identify antibacterial peptides present in a pepsin digest of ovine αs2-casein. A protein digest with antibacterial properties was first separated by ion exchange chromatography. The fractions most active against Escherichia coli ATCC 25922 were fractionated by semi-preparative RP-HPLC, and the identification of the active peptides was carried out by on-line and off-line RP-HPLC-ESI-MS/MS. Following this strategy, 10 different peptides were identified, all corresponding to the C-terminal region of the ovine αs2-casein. Four of them were chemically synthesized and showed antibacterial activity against several Gram-positive and Gram-negative bacteria. Among the synthesized peptides, ovine αs2-casein f(165181) exhibited the highest antibacterial potency against all bacteria tested. The antimicrobial activity was compared with that of other previously described peptides like lactoferricin and fragment f(183207) of bovine αs2-casein.
Keywords: [alpha]s2-Casein; Antibacterial peptide; Electrospray mass spectrometry; Ovine milk
Citation: 2

Casein hydrolysates as a source of antimicrobial, antioxidant and antihypertensive peptides

Cited Entries: CAA0026

Authors:Lopez-Exposito, I., Quiros, A., Amigo, L., Recio, I.
Journal: Lait 2007, 87(4-5).
Abstract: The aim of this work was to investigate the presence of antioxidant and ACE-inhibitory activity in ovine alpha(s2)-casein and bovine kappa-casein hydrolysates with antibacterial activity. Several peptides which had been previously identified in these hydrolysates were selected in order to fulfil certain structural requirements and they were chemically synthesised to evaluate their antioxidant and ACE-inhibitory activity. Hydrolysates of ovine alpha s2-casein and bovine kappa-casein with pepsin strongly inhibited ACE activity, with IC50 values of 41.8 and 9.97 mu mol.L-1, respectively. The kappa-casein hydrolysate also exhibited a significant oxygen radical absorbance capacity, seven times higher than that of Trolox. From the chemically synthesised peptides, two of them, LKKISQ and PYVRYL, both from ovine alpha(s2)-casein, exerted potent ACE-inhibitory activity in the range of the most potent food-derived antihypertensive peptides described to date (IC50 values of 2.6 and 2.4 mu mol.L-1, respectively). The latter sequence, corresponding to the C-terminal hexapeptide of the ovine alpha(s2)-casein molecule, also had antioxidant activity. The activity found is discussed in relation to the peptide sequences.
Keywords: alpha(s2)-casein / kappa-casein / antibacterial activity / antioxidant activity / angiotensin-converting enzyme-inhibitory activity / bioactive peptide

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