Apo-α-lactalbumin [id=ALA0001]

Producer Organism : Native Protein : Production Method :
Human α-lactalbumin LC method/EDTA treatment and LC method
Activity : Antibacterial
Target Organisms :

Gram-positive: Active against Streptococcus mitis, Streptococcus pyogenes at 2 mg/ml, Streptococcus pmeumoniae L14060-92, Streptococcus pmeumoniae L15256-92, Streptococcus pmeumoniae L14326-92, Streptococcus pmeumoniae L15006-92), Streptococcus pmeumoniae CCUG 10175, Streptococcus pmeumoniae L14117-92, Streptococcus pmeumoniae L14612-92, Streptococcus pmeumoniae L14423-92, Streptococcus pmeumoniae L14007-92 (MIC<0.06 mg/ml), Streptococcus pmeumoniae SA 44165, Streptococcus pmeumoniae L14091-92, Streptococcus pmeumoniae L1828, Streptococcus pmeumoniae L317-93, Streptococcus pmeumoniae L1017-93, Streptococcus pmeumoniae L859, Streptococcus pmeumoniae L963, Streptococcus pmeumoniae L14030-92, Streptococcus pmeumoniae BN241-94, Streptococcus pmeumoniae DK 84/87 (MIC>2 mg/ml).

Gram-negative: Active against Haemophilus influenzae, Moraxella catharralis at 2 mg/ml.

NOTE: No activity against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus sanguis, Streptococcus mutans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Haemophilus parainfluenzae, Enterobacter cloache, Enterococcus faecalis, Streptococcus sp. at 2 mg/ml .

Description :
Production method: Isolated from human milk casein by anion exchange chromatography followed by size exclusion chromatography/EDTA treatment and ion-exchange chromatography.

Removal of the Ca2+ ion was required to open up the protein, and oleic acid served to stabilize and preserve the bactericidal conformation.
Citation: 1

A folding variant of a-lactalbumin with bactericidal activity against Streptococcus pneumoniae

Cited Entries: ALA0001

Authors:Hakansson, A., Svensson, M., Mossberg, A.-K., Sabharwal, H., Linse, S., Lazou, I., Lonnerdal, B., Svanborg, C.
Journal: Molecular Microbiology 2000, 35(3).
Abstract: This study describes an alpha-lactalbumin folding variant from human milk with bactericidal activity against antibiotic-resistant and -susceptible strains of Streptococcus pneumoniae. The active complex precipitated with the casein fraction at pH 4.6 and was purified from casein by a combination of anion exchange and gel chromatography. Unlike other casein components, the active complex was retained on the ion-exchange matrix and eluted only with high salt. The eluted fraction showed N-terminal and mass spectrometric identity with human milk alpha-lactalbumin, but native alpha-lactalbumin had no bactericidal effect. Spectroscopic analysis demonstrated that the active form of the molecule was in a different folding state, with secondary structure identical to alpha-lactalbumin from human milk whey, but fluctuating tertiary structure. Native alpha-lactalbumin could be converted to the active bactericidal form by ion-exchange chromatography in the presence of a cofactor from human milk casein, characterized as a C18:1 fatty acid. Analysis of the antibacterial spectrum showed selectivity for streptococci; Gram-negative and other Gram-positive bacteria were resistant. The folding variant of alpha-lactalbumin is a new example of naturally occurring molecules with antimicrobial activity.

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