Redox equilibrium of sperm-whale myoglobin, Aplysia myoglobin, and Chironomus thummi hemoglobin

Brunori, Maurizio; Saggese, Ughetta; Rotilio, G.; Antonini, Eraldo; Wyman, Jeffries

doi:10.1021/bi00785a016

Cited by 82 publications

(36 citation statements)

References 23 publications

(23 reference statements)

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“…The midpoint potential determined significantly differs from the midpoint potential of Mb in solution, which is 0.06 V versus SHE at pH 5.5 [30,31]. This could be related to either a change in the heme environment of the protein or a local electric field, as has been reported for cytochrome c immobilized on carboxylic acid terminated self-assembled monolayers [32][33][34][35].…”

Section: Preparation Of a Pdda-pss-heme-pdda-pss Layer On Pyrolitic Gmentioning

confidence: 67%

Evidence for heme release in layer-by-layer assemblies of myoglobin and polystyrenesulfonate on pyrolitic graphite

2007

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Layer-by-layer assemblies of myoglobin and polystyrenesulfonate (PSS) on pyrolitic graphite have been investigated with the goal of determining the origin of the voltammetric response of these films. From the similar midpoint potential, coverage and electron transfer behavior compared with those of adsorbed free heme, it was concluded that the observed voltammetric peak is due to heme adsorbed at the electrode surface. This suggests that the interactions between the pyrolitic graphite electrode, PSS and myoglobin can result in heme release from the protein followed by heme adsorption on the electrode.

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Section: Preparation Of a Pdda-pss-heme-pdda-pss Layer On Pyrolitic Gmentioning

confidence: 67%

Evidence for heme release in layer-by-layer assemblies of myoglobin and polystyrenesulfonate on pyrolitic graphite

2007

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“…A half-reduction potential of protoheme moiety measured by potentiometric method with a combination of dyes gave a value of -60 mV in 0.1 M potassium phosphate buffer pH 7.0 a t 25 "C. This value is significantly lower than those of myoglobin (50 mV) [33] and hemoglobin (150 mV) [34]. A half-reduction potential of FAD moiety was measured to be about --150 mV by this method and the n value of the titration curve was 1.3 -1.6, which is smaller than the theoretically expected value of 2.0.…”

Section: Oxygen Equilibrium Of the Purified Yeast Hemoglobinmentioning

confidence: 87%

Purification and Molecular Properties of Yeast Hemoglobin

Oshino

Asakura

Takio

et al. 1973

European Journal of Biochemistry

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Yeast hemoglobin from Candida mycoderma has been purified by ammonium sulfate fractionation and subsequent DEAE-cellulose column chromatography, A minimum molecular weight estimated from the result of amino acid analysis, as well as dodecylsulfate gel electrophoresis and gel filtration on Sephadex G-100, is 50000. The absorption spectra of ferrous yeast hemoglobin in the oxy, deoxy and carboxy forms were almost identical to those of other hemoglobins, with the exception of a small contribution from flavin. The molecule has two prosthetic groups, FAD and protoheme. The results obtained by dodecylsulfate-gel electrophoresis and 8 M urea treatment suggest that both prosthetic groups are attached on a single peptide chain, which appears to exist as a monomer. Yeast hemoglobin, in the ferrous form, is capable of binding oxygen reversibly. The oxygen affinity of yeast hemoglobin is 20 nM (0.01 mm Hg) and a rate constant of oxygen dissociation is 17 s-l a t pH 7.0, 23 "C. Half-reduction potentials of heme and 0avin moieties were -60 mV and about -150 mV, respectively, in 0

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“…This hypothesis again fits the concept of Waks and Alfsen [3], who suggested the different haptoglobins t o represent polymerization products of a common unit. However, the equivalence of the binding sites in both schemes contradicts the mechanism proposed by Waks et al [2] and Brunori et al [4], who consider only one type of association in case of H b + Hp, while in Hp + Hb different types of binding of the ap-dimer are postulated.…”

Section: Discussionmentioning

confidence: 79%

“…It seems generally accepted [2,[4][5][6]151, that the reactive unit in the Hb-Hp interaction is the ap-dimer of Hb. Assuming the Hp-(o~/?)…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, Brunori et a1. [4] pointed out that the shape of the redox equilibrium curve of H b changes with the molar ratio Hb:Hp, indicating that a t H p : H b = 2: 1 only one type of complex is formed, while a t Hp:Hb = 1:1 more than one type is present. Following the quenching of the Hp fluorescence upon H b binding, Nagel and Gibson [5] postulated the &-chain of Hb to be the only reacting component, the tetrameric state not being reactive.…”

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confidence: 99%

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On the Mechanism of Hemoglobin‐Haptoglobin Complex Formation

Pavlı́ček

Jaenicke

1971

European Journal of Biochemistry

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In order to elucidate the mechanism of complex formation between human haptoglobin, Hp II, and bovine hemoglobin, Hb, measurements of the peroxidase activity and histidine determinations, as well as spectrophtometric and optical rotatroy dispersion titration experiments were performed. Following the raaction by slowly mixing the constituents of the complex in small portinos, the geometry of the complex turns out to depend on the sequence of mixing of the reactants. Adding Hb to Hp, a final complex Hb2→ Hp is formed. Teh inverse sequence of mixing leads to a complex of identical composition (Hp → Hb2), but different arrangement of the constituents, as shown by differences in the accessibility of histidine residues in both types of the complex. As suggested by the comparison of the histidine balance of both complexes, Hb2→ Hp may be described by the combination of αβ‐dimers of Hb with Hp (Hp (αβ)4), while Hp → Hb2 corresponds to the complex with two Hb tetramers (Hp(α2β2)2). Investigating the saturation process of complex formation in greater detail by spectrophtometric titration and optical rotatory dispersion, intermediary complexes are observed which prove the mechanism of complex formation to be a consecutive association process. Both series of complexes, Hp → Hb and Hb → Hp, seem to generate closely related configurations characterized by similar spectral and functional properties.

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Redox equilibrium of sperm-whale myoglobin, Aplysia myoglobin, and Chironomus thummi hemoglobin

Cited by 82 publications

References 23 publications

Evidence for heme release in layer-by-layer assemblies of myoglobin and polystyrenesulfonate on pyrolitic graphite

Evidence for heme release in layer-by-layer assemblies of myoglobin and polystyrenesulfonate on pyrolitic graphite

Purification and Molecular Properties of Yeast Hemoglobin

On the Mechanism of Hemoglobin‐Haptoglobin Complex Formation

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