Casein proteolysis in human milk: tracing the pattern of casein breakdown and the formation of potential bioactive peptides.
The protein and peptide fraction of human milk samples collected from mothers of pre- and full-term infants in the first week after parturition was analysed by use of liquid chromatography-mass spectrometry and tandem mass spectrometry. By characterising the peptide sequence, we defined the pathway of casein hydrolysis which leads to the formation of small peptides through intermediate oligopeptides. It was found that the action of a plasmin-like enzyme acting on specific lysine residues is the primary step in casein degradation. This is followed by endopeptidases and/or exopeptidases mediated cleavage of the oligopeptides which, in turn, produces a multiplicity of short peptides differing by one or more amino acid residues. In this process, a series of potentially bioactive peptides (opioid, phosphopeptides) and their precursors are produced.
Ferranti
Pasquale
P
Dipartimento di Scienza degli Alimenti, Università degli Studi di Napoli Federico II, Portici, Italy. ferranti@unina.it
Traisci
Maria Vittoria
MV
Picariello
Gianluca
G
Nasi
Antonella
A
Boschi
Velia
V
Siervo
Mario
M
Falconi
Claudio
C
Chianese
Lina
L
Addeo
Francesco
F
D000595:Amino Acid Sequence; D002364:Caseins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D019281:Dimerization; D010450:Endopeptidases / Q000378:metabolism; D020689:Exopeptidases / Q000378:metabolism; D005260:Female; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008239:Lysine / Q000378:metabolism; D013058:Mass Spectrometry; D008895:Milk, Human / Q000737:chemistry* / Q000201:enzymology; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010455:Peptides / Q000032:analysis*; D020539:Sequence Analysis, Protein; D012995:Solubility; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014238:Trichloroacetic Acid
D002364:Caseins; D010455:Peptides; D014238:Trichloroacetic Acid; D010450:Endopeptidases; D020689:Exopeptidases; D005341:Fibrinolysin; D008239:Lysine