αs2-casein f(179-194) [id=CAA0013]

Synonym: L-16-Y

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

Gram-positive: Micrococcus flavus DSM 1790 (MIC=75 然), Listeria innocua (MIC=50 然), Bacillus cereus P7 (MIC=75 然), Streptococcus thermophilus Rs (MIC=50 然).

Gram-negative: Escherichia coli ATCC 25922 (MIC=25 然), Escherichia coli MC 1061 (MIC=99 然).

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

Length : 16 Mass (Da): 2 012.32 Common Amino Acids : KQ
Isolectric Point : 10.73 Net Charge : 4 Absent Amino Acids : CDEGHMNTVW
Basic Residues : 4 Acidic Residues : 0 Hydrophobic Residues : 5
Polar Residues : 3 Boman Index : -32.32 Hydropathy Index : -0.938
Aliphatic Index : 79.38 Instability Index : 0 Extinction Coefficient : 2980
Absorbance 280nm : 198.67

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.

Multiple Sequence Alignment (MSA)

 2 CAA0020   100.0%  ---------------------------------VYQHQKAMKPWIQPKTKVIPYVRYL 
 3 CAA0021   100.0%  ---------------------------------VYQHQKAMKPWIQPKTKVIPYVRYL 
 4 CAA0019   100.0%  -------------------------------KTVYQHQKAMKPWIQPKTKVIPYVRYL 
 5 CAA0018   100.0%  ------------------------------LKTVYQHQKAMKPWIQPKTKVIPYVRYL 
 6 CAA0017   100.0%  -------------------------ALPQYLKTVYQHQKAMKPWIQPKTKVIPYVRYL 
 7 CAA0015   100.0%  ----------------------QKFALPQYLKTVYQHQKAMKPWIQPKTKVIPYVRYL 
 9 CAA0009   100.0%  --------KNRLNFLKKISQRYQKFALPQYLKTVYQHQK------------------- 

10 CAA0013   100.0%  --------------LKKISQRYQKFALPQY---------------------------- 

11 CAA0008   100.0%  --------KNRLNFLKKISQRYQ----------------------------------- 




15 CAA0012   100.0%  --------------------RYQKFALPQYLKTVYQHQK------------------- 

16 CAA0016   100.0%  ------------------------FALPQYLK-------------------------- 

Citation: 1

Identification of two distinct antibacterial domains within the sequence of bovine alphas2-casein

Cited Entries: CAA0013, CAA0019, CAA0020

Authors:Recio, I., Visser, S.
Journal: Biochimica et Biophysica Acta (BBA) - General Subjects 1999, 1428(2-3).
CrossRef External Link
Abstract: Two distinct domains with antibacterial activity were isolated from a peptic hydrolysate of bovine αs2-casein. The digested αs2-casein was fractionated by cation-exchange chromatography, after which the peptides in the two active fractions obtained were separated by high-performance liquid chromatography and sequenced by electrospray-ionization tandem mass spectrometry. The major component in each active fraction, f(183207) and f(164179), was further purified and the antibacterial activity of these components was tested against several microorganisms. Depending on the target bacterial strain, these peptides exhibited minimum inhibitory concentrations between 8 and 99 μM. Peptide f(183207) exhibited a consistently higher antibacterial activity than f(164179), although both peptides showed a comparable hemolytic effect. A method of in situ enzymatic hydrolysis on a cation-exchange membrane to obtain a fraction enriched in the most active antibacterial domain is presented. The antibacterial and hemolytic activities are discussed in relation to the structure and hydrophobicity of the peptides.
Keywords: Antibacterial peptide; [alpha]s2-Casein; Electrospray mass spectrometry; Hydrolysis of membrane-bound protein
Citation: 2

Two ion-exchange chromatographic methods for the isolation of antibacterial peptides from lactoferrin: In situ enzymatic hydrolysis on an ion-exchange membrane

Cited Entries: LFB0006, LFB0010, LFB0085, LFB0092, LFB0147, LFB0148, LFB0151, CAA0013, CAA0019, CAA0020

Authors:Recio, I., Visser, S.
Journal: Journal of Chromatography A 1999, 831(2).
CrossRef External Link
Abstract: Two ion-exchange chromatographic methods are reported for the rapid isolation of antibacterial peptides from lactoferrin (LF). Using the first method, a pepsin hydrolysate of LF was fractionated by bead-based cation-exchange chromatography. After removal of weakly bound material by washing with ammonia, highly purified lactoferricin-B (LFcin-B) was obtained in a single step by elution with 2 M NaCl. Some other cationic peptides, copurified as minor components, were also characterised by N-terminal sequencing, mass spectrometry and antibacterial activity determination. With the second method, cheese whey was filtered through a cation-exchange membrane, and the selectively bound LF was directly hydrolysed in situ with pepsin. Inactive LF fragments were washed off the membrane with ammonia, and a fraction enriched in LFcin-B was obtained by further elution with 2 M NaCl. The membrane method is more rapid and offers several economic advantages.
Keywords: peptides; ANTIBACTERIAL agents; Lactoferrin

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