The binding of Fe+++ to native and chemically modified human serum albumin in the presence of sodium citrate

Coddington, A.; Perkins, D.J.

doi:10.1016/0006-3002(60)91577-8

Cited by 12 publications

(7 citation statements)

References 3 publications

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“…Coddington & Perkins (1960) found similar results in their study of the binding of Fe3+ ions to human albumin in the presence of citrate. This indicates that in the compact molecule the localization of regions of charge is responsible for the binding of the charged citrate complex.…”

Section: Vol 84 155supporting

confidence: 67%

Studies on the interaction of magnesium, calcium and strontium ions with native and chemically modified human serum albumin

Irons

Perkins

1962

Biochemical Journal

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The interactions of Ca2+ ions with plasma proteins were first studied by Pribram (1871) Mg2+, Ca2+ > Sr2+> Ba2+ ions, although Mg2+ ion is often irregular in position (Schubert, 1954).In this paper an attempt has been made to extend this work by comparing the binding of the alkaline-earth ions to native and chemically modified human albumin over a range of pH and in the presence of near-physiological concentrations of Na+ ions. Additional information about the nature of the binding sites on albumin for these ions is given. Greenwald (1926) Measurement of radioactivity. The method of isotope dilution was used for the quantitative determination of metal ions. The isotope 28Mg was counted with a wellcrystal system in conjunction with an automatic scaler.The isotopes 45Ca and 89Sr were counted by a p-particle liquid-scintillation technique at -17°. Diphenyloxazole (0-3 %, w/v) in toluene was used as the organic scintillator. Aqueous samples (1 ml.) were blended with a scintillator (5 ml.) with ethanol (10 ml.). Protein solutions were precipitated by the ethanol in the counting solution. When the precipitated protein was allowed to settle in the counting dish it did not appreciably affect the count. In practice, therefore, the protein was precipitated and kept for at least 3-4 hr. in the dish at -17°before counting. Solutions containing buffer ions in the presence and absence of protein were counted with the same efficiency as an aqueous solution containing the same amount of activity. Each sample was counted for a minimum of 150 000 counts.Equilibrium dialysis. All dialyses were carried out with 10 ml. of 0-5-0-7% (w/v) protein-buffer solution inside Visking cellulose membranes. The outer solution (120-140 ml.) was of measured pH and molarity 0-15-0-17.Each dialysis was done in a dialysis rocker overnight at room temperature. Control experiments showed that with this apparatus 0-10m-sodium chloride came into equilibrium with water in 3 hr. Dialysis experiments as a function of pH were carried out at fixeed Ca2+, Mg2+ and Sr2+ ion concentrations of 20, 10 and 40 mg./l. respectively.Outer buffer solutions. The following buffer systems were used: pH 2-4, 0-05M-potassium hydrogen phthalate; pH4-6, 0-05M-sodium acetate-acetic acid; pH6-7-5,0-02M-sodium cacodylate; pH 8-9-5, 0-lm-sodium hydroxideboric acid-potassium chloride. Sodium chloride was added to each buffer solution to bring the molarity to 0-15-0-17.Protein concentration. Protein was estimated by a semimicro-Kjeldahl technique; a protein:N factor of 6-25 was assumed.

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Section: Vol 84 155supporting

confidence: 67%

Studies on the interaction of magnesium, calcium and strontium ions with native and chemically modified human serum albumin

Irons

Perkins

1962

Biochemical Journal

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“…Ku (1958) found that heparin inhibited liver and other phenyl phosphatases, an effect attributed to a possible direct combination through a salt linkage of heparin sulphonic acid groups with amino groups of the enzyme. Coddington & Perkins (1960) showed that citrate makes possible a union of Fe3+ ions with serum albumin, in line with previous observations quoted by these authors which demonstrated that the formation of an ironcitrate complex possessing a net negative charge permits binding of iron to positively-charged sites on proteins. The close proximity of stored iron and acid phosphatase in siderotic-liver lysosomes and phagosomes (de Duve & Beaufay, 1957;Beaufay et al 1959;Novikoff, 1960;Essner & Novikoff, 1960, 1961 raised the possibility that under these circumstances citrate forms a complex with Fe3+ ions bound to apoferritin; and that this ironcitrate complex then becomes attached to the enzyme, perhaps bringing about activation by displacing phosphate or one of a number of other possible inhibitors (see below).…”

Section: Discussionsupporting

confidence: 89%

Biochemical changes in the tissues of animals injected with iron. 4. The nature of acid-phosphatase activity

Golberg¹,

Martin²,

Leigh³

1962

Biochemical Journal

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Golberg, Martin & Batchelor (1960) showed that treatment of mice and rats with heavy doses of iron-dextran complex increased the activity of acid phosphatase and other lysosomal enzymes, not only in liver but also in organs such as spleen and kidney which display low activity in the untreated animal. Some of the largest increases were found at the sites of repeated injections given into the thigh muscles or in the subcutaneous tissues of the abdominal wall, changes clearly reflecting the morphological and cytological alterations which are induced locally under these circumstances

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“…Serum albumin has been suggested as a candidate for the protein component of NTBI. 7,8 The capacity of human serum albumin to bind iron or iron citrate at low pH was demonstrated by Coddington and Perkins, 9 and the interaction of bovine serum albumin with iron and iron citrate complexes was reported by Løvstad. 10 Hider and co-workers 11,12 have presented convincing evidence that NTBI is composed in part of serum albumin.…”

Section: ■ Introductionmentioning

confidence: 96%

“…NTBI is composed of Fe, citrate, and albumin: Grootveld et al found NMR and HPLC evidence to suggest that NTBI in blood fractions from hemochromatosis patients is largely iron citrate, with possible contributions iron–citrate–acetate and protein-bound iron/iron citrate. Serum albumin has been suggested as a candidate for the protein component of NTBI. , The capacity of human serum albumin to bind iron or iron citrate at low pH was demonstrated by Coddington and Perkins, and the interaction of bovine serum albumin with iron and iron citrate complexes was reported by Løvstad . Hider and co-workers , have presented convincing evidence that NTBI is composed in part of serum albumin.…”

Section: Introductionmentioning

confidence: 98%

Redox Properties and Activity of Iron–Citrate Complexes: Evidence for Redox Cycling

Adam

Bounds

Kissner

et al. 2015

Chem. Res. Toxicol.

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Iron in iron overload disease is present as non-transferrin-bound iron, consisting of iron, citrate, and albumin. We investigated the redox properties of iron citrate by electrochemistry, by the kinetics of its reaction with ascorbate, by ESR, and by analyzing the products of reactions of ascorbate with iron citrate complexes in the presence of H2O2 with 4-hydroxybenzoic acid as a reporter molecule for hydroxylation. We report -0.03 V < E°' > +0.01 V for the (Fe(3+)-cit/Fe(2+)-cit) couple. The first step in the reaction of iron citrate with ascorbate is the rapid formation of mixed complexes of iron with citrate and ascorbate, followed by slow reduction to Fe(2+)-citrate with k = ca. 3 M(-1) s(-1). The ascorbyl radical is formed by iron citrate oxidation of Hasc(-) with k = ca. 0.02 M(-1) s(-1); the majority of the ascorbyl radical formed is sequestered by complexation with iron and remains EPR silent. The hydroxylation of 4-hydroxybenzoic acid driven by the Fenton reduction of iron citrate by ascorbate in the presence of H2O2 proceeds in three phases: the first phase, which is independent of the presence of O2, is revealed as a nonzero intercept that reflects the rapid reaction of accumulated Fe(2+) with H2O2; the intermediate oxygen-dependent phase fits a first-order accumulation of product with k = 5 M(-1) s(-1) under aerobic and k = 13 M(-1) s(-1) under anaerobic conditions; the slope of the final linear phase is ca. k = 5 × 10(-2) M(-1) s(-1) under both aerobic and anaerobic conditions. Product yields under aerobic conditions are greater than predicted from the initial concentration of iron, but they are less than predicted for continuous redox cycling in the presence of excess ascorbate. The ongoing formation of hydroxylated product supports slow redox cycling by iron citrate. Thus, when H2O2 is available, iron-citrate complexes may contribute to pathophysiological manifestations of iron overload diseases.

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The binding of Fe+++ to native and chemically modified human serum albumin in the presence of sodium citrate

Cited by 12 publications

References 3 publications

Studies on the interaction of magnesium, calcium and strontium ions with native and chemically modified human serum albumin

Studies on the interaction of magnesium, calcium and strontium ions with native and chemically modified human serum albumin

Biochemical changes in the tissues of animals injected with iron. 4. The nature of acid-phosphatase activity

Redox Properties and Activity of Iron–Citrate Complexes: Evidence for Redox Cycling

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