Iron(III)-phosphoprotein chelates: stoichiometric equilibrium constant for interaction of iron(III) and phosphorylserine residues of phosvitin and casein

Hegenauer, Jack; Saltman, Paul; Nace, George W.

doi:10.1021/bi00585a006

Cited by 93 publications

(70 citation statements)

References 51 publications

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“…and Fe 3? through anion clusters formed by acidic amino acids and phosphorylserine residues (Loh and Kaldor 1973;Hegenauer et al 1979;Singh et al 1989;Reddy andMahoney 1991: Farrel et al 2004;McMahon and Oommen 2008). To further elucidate the physiological meaning of the binding mechanism of bovine spleen ferritin with a-casein, at first, FAS was used to test the possibility of the involvement of ferrous iron in the bindings.…”

Section: Resultsmentioning

confidence: 99%

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Heme-mediated binding of α-casein to ferritin: evidence for preferential α-casein binding to ferrous iron

et al. 2011

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Bovine milk α-casein was identified as a ferritin-binding protein, and ferritin is known to be a heme-binding protein. In this study, we found that the binding of α-casein to bovine spleen ferritin in vitro was blocked by hemin, but not by iron-free hemin (protoporphyrin IX) or zinc-protoporphyrin IX, suggesting that the presence of iron in heme play a key role in this interaction. Indeed, the binding of α-casein to ferritin and biotinylated hemin was inhibited by adding excess ferrous ammonium sulfate (FAS). To further elucidate the binding mechanism of α-casein to biotinylated hemin, Ferrozine and nitrilotriacetic acid (NTA) were used as ferrous and ferric iron chelators, respectively. FAS-mediated inhibition of α-casein to biotinylated hemin was neutralized with Ferrozine, but not NTA, while FAS- as well as ferric chloride-mediated inhibition in their interaction was neutralized by NTA. The following ions also inhibited α-casein-biotinylated hemin binding in order of potency of inhibition: FAS (Fe(2+)) << ferric chloride (Fe(3+)) < copper sulfate (Cu(2+)) < zinc sulfate (Zn(2+)) < manganese chloride (Mn(2+)) < calcium chloride (Ca(2+)) < magnesium sulfate (Mg(2+)). These results suggests that the binding of α-casein to ferritin is heme-mediated through direct binding of α-casein to iron in the heme on the surface of ferritin molecule, and that α-casein preferentially binds Fe(2+) compared with any other metal ions, including Fe(3+).

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Section: Resultsmentioning

confidence: 99%

“…and Fe 3? through anion clusters formed by acidic amino acids and phosphorylserine residue (Loh and Kaldor 1973;Hegenauer et al 1979;Singh et al 1989;Reddy and Mahoney 1991;Farrel et al 2004;McMahon and Oommen 2008).…”

Section: Introductionmentioning

confidence: 99%

Heme-mediated binding of α-casein to ferritin: evidence for preferential α-casein binding to ferrous iron

et al. 2011

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“…11) The strength of Fe(III) binding is 10 17{18 M; 12) that of Fe(II) is much lower. 13) Synthesized in the liver, phosvitin is a segment of a large precursor protein, vitellogenin, which circulates in the blood of the egg-laying animal.…”

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confidence: 99%

Egg Yolk Phosvitin Inhibits Hydroxyl Radical Formation from the Fenton Reaction

Ishikawa

Yano

Arihara

et al. 2004

Bioscience, Biotechnology, and Biochemistry

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Phosvitin, a phosphoprotein known as an iron-carrier in egg yolk, binds almost all the yolk iron. In this study, we investigated the effect of phosvitin on Fe(II)-catalyzed hydroxyl radical ( OH) formation from H 2 O 2 in the Fenton reaction system. Using electron spin resonance (ESR) with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and deoxyribose degradation assays, we observed by both assays that phosvitin more effectively inhibited OH formation than iron-binding proteins such as ferritin and transferrin. The effectiveness of phosvitin was related to the iron concentration, indicating that phosvitin acts as an antioxidant by chelating iron ions. Phosvitin accelerates Fe(II) autoxidation and thus decreases the availability of Fe(II) for participation in the OH-generating Fenton reaction. Furthermore, using the plasmid DNA strand breakage assay, phosvitin protected DNA against oxidative damage induced by Fe(II) and H 2 O 2 . These results provide insight into the mechanism of protection of the developing embryo against iron-dependent oxidative damage in ovo.

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“…The presence of a "negative cluster" of phosphoseryl residues at the positions 15, 17, 18 and 19 enables iron chelation [4]. This cluster plays an important role since the affinity of β-caseinophosphopeptide (f1-25) (4 phosphoseryl residues) for chelating iron [4 to 6 atoms/ mol β-caseinophosphopeptide (f1-25)] is greater than that of the other β-casein phosphopeptide (f33-48) containing only one phosphoseryl residue [4,8,19,27,58]. Chelation of iron decreases its availability and its catalytic efficiency [13], but induces oxygen consumption during fixation and oxidation of the metal ion.…”

Section: Discussionmentioning

confidence: 99%

?-Caseinophosphopeptide (f1-25) confers on ?-casein tryptic hydrolysate an antioxidant activity during iron/ascorbate-induced oxidation of liposomes

Kansci

Génot²,

Meynier³

et al. 2004

Lait

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-Protein ingredients such as hydrolysates of milk proteins may improve the nutritive value of functional foods. For instance, β-casein tryptic hydrolysate could simultaneously increase iron absorption and prevent lipid oxidation in foods containing high contents of polyunsaturated fatty acids (PUFA). The aim of this study was to determine the antioxidant activity of β-casein tryptic hydrolysate and of its β-caseinophosphopeptide (f1-25) on Fe(III)/ascorbate-induced oxidation of muscle phospholipids in a liposome system. Oxygen consumption, conjugated dienes (CD), thiobarbituric acid reactive substances (TBARS) and volatile compounds were measured during oxidation at 25 °C of the liposomes in the presence of either the β-casein tryptic hydrolysate (0.24-2.4 mg·mL -1 ) or of its phosphopeptide (0.1-0.31 mg·mL -1 ). Oxygen consumption was significantly enhanced in the presence of β-casein tryptic hydrolysate or of the phosphopeptide (f1-25) and staircase curves were observed for the highest concentrations, showing complex oxidative interactions between iron, β-casein tryptic hydrolysate or phosphopeptide and the phospholipids. In contrast, on an hourly scale, formation of CD, TBARS and total volatile compounds were inhibited. The inhibition of CD and TBARS reached 50% after 20 h of oxidation in the presence of 1.2 mg·mL -1 β-casein tryptic hydrolysate or 0.16 mg·mL -1 phosphopeptide (f1-25). Amounts of total volatile compounds produced after 24 h decreased by about 60% in the presence of the hydrolysate (1.2 mg·mL -1 ) and 50% with the phosphopeptide (f1-25) (0.31 mg·mL -1 ) due to drastic decrease or even disappearance of alkanals and 2-alkenals. Several alcohols such as pentanol and hexanol were produced in higher amounts. Thus β-casein tryptic hydrolysate can protect rich-in-PUFA phospholipid liposomes against long-term iron-induced oxidation, mainly due to iron chelation by β-caseinophosphopeptide (f1-25). This antioxidant activity could benefit specific food products.

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Iron(III)-phosphoprotein chelates: stoichiometric equilibrium constant for interaction of iron(III) and phosphorylserine residues of phosvitin and casein

Cited by 93 publications

References 51 publications

Heme-mediated binding of α-casein to ferritin: evidence for preferential α-casein binding to ferrous iron

Heme-mediated binding of α-casein to ferritin: evidence for preferential α-casein binding to ferrous iron

Egg Yolk Phosvitin Inhibits Hydroxyl Radical Formation from the Fenton Reaction

?-Caseinophosphopeptide (f1-25) confers on ?-casein tryptic hydrolysate an antioxidant activity during iron/ascorbate-induced oxidation of liposomes

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