1. Bioactive peptides derived from human milk proteins — mechanisms of action 
Yasuaki Wada, Bo Lönnerdal 
Journal of Nutritional Biochemistry 
Volume 25, Issue 5, Pages (May 2014)
DOI: /j.jnutbio
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2. Fig. 1
Major pathways for intestinal absorption of bioactive peptides. Mechanisms for absorption of bioactive peptides in the intestine are largely categorized into carrier-mediated transport, transcytosis and paracellular passive diffusion. Among them, paracellular passive diffusion is a non-digestive route, and peptides are likely to be absorbed in intact form.
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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3. Fig. 2
Putative CPP-mediated calcium absorption in the small intestine. CPPs form soluble complexes with Ca2+ in the lumen of the small intestine, preventing its precipitation. At the luminal surface, the acidic microclimate pH dissociates the complex, and (A) the released Ca2+ enters passive diffusion, and/or (B) CPPs activate uptake of released Ca2+ through calcium channels by modifying the apical membrane potential.
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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4. Fig. 3
Decoy effect of glycomacropeptide (GMP) inhibiting bacterial adhesion to gastrointestinal mucosa. (A) Many pathogenic bacteria bind to oligosaccharide residues of the gastrointestinal mucosa at the onset of infection. (B) The glycosylated motif in GMP serves as a ‘decoy’ for pathogenic bacteria, thereby inhibiting bacterial adhesion to the mucosa.
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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5. Fig. 4
Primary structures of lactoferricin (Lfcin) H and B. Lfcin H and B are shown in (A) and (B), respectively. Single-letter codes are used to indicate amino acid sequences of the peptides, and basic amino acid residues are shaded [89].
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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6. Fig. 5
Primary structures of bifidogenic peptides derived from human and bovine lactoferrin. Human LF-derived peptides are shown in (A) and (B), and a bovine counterpart is depicted in (C). Single-letter codes are used to indicate amino acid sequences of the peptides, and proteolytic variants are shown in gray [21,101].
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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7. Fig. 6
The role of ACE in blood pressure control. In the renin-angiotensin system, ACE converts Angiotensin I by cleaving the C-terminal dipeptides residues into the potent vasoconstricting angiotensin II. In the kallikrein-kinin system, it degrades the a potent vasodilating kinin. Therefore, inhibition of ACE has long been targeted for treatment of hypertension.
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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8. Fig. 7
Schematic diagram of the interaction between ACE and its inhibitory peptides. This figure has been published previously [112], but is modified here by featuring a human β-casein-derived ACE-inhibitory peptide (HLPLP) [113]. This peptide may interact hydrophobically with the S1, S’1 and S’2 subsites at the active site of ACE thereby inhibiting the activity. Hydrogen bonds and ionic bonds are also likely to facilitate the interaction considerably.
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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9. Fig. 8
Putative major sites of action and bioactivity of orally ingested milk protein (casein)-derived opioid peptides in newborns. Possibly due to the incomplete digestion and a more permeable gastrointestinal barrier in newborn animals, opioid peptide precursors are formed after milk protein ingestion and absorbed. The precursors partly resist digestion in the intestinal wall and blood circulation, and certain amounts of resulting opioid peptides may be delivered to the enteric nerve and the central nervous system, exerting their bioactivity.
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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10. Fig. 9
Quenching of free radicals by ring structures of amino acid residues. Amino acid residues such as Trp and Tyr serve as hydrogen donors, and stabilize radicals through resonance and delocalization. Radical scavenging by Trp is shown here [166].
Journal of Nutritional Biochemistry  , DOI: ( /j.jnutbio )
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