Studies on acetylated human hemoglobin

Bucci, Enrico; Fronticelli, Clara; Bellelli, L; Antonini, Eraldo; Wyman, Jeffries; Fanelli, A.

doi:10.1016/0003-9861(63)90099-7

Cited by 22 publications

(8 citation statements)

References 11 publications

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“…Acetylated derivatives always give more homogeneous bands than the succinylated ones. Moreover, heterogeneity decreases with increasing degree of acylation (Bucci et al, 1963). In particular, 30% acetylation suffices to yield relatively homogeneous preparations of HbII, HbA and Mb, but not of HbI, in agreement with the higher number of lysyl residues of the last protein ( Fig.…”

Section: Modification Of Amino Groupssupporting

confidence: 69%

Structural and functional effects of selective chemical modifications of Scapharca inaequivalvis haemoglobins in relation to their unique assembly

Boffi¹,

Gattoni²,

Santucci³

et al. 1987

Biochemical Journal

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The structural and functional roles of lysyl and thiol groups in the dimeric (HbI) and tetrameric (HbII) haemoglobins from the mollusc Scapharca inaequivalvis have been assessed. In these haemoglobins a unique mode of assembly (the haem-carrying E and F helices form the intersubunit contact of the dimeric unit) is associated with co-operative oxygen binding. Extensive acylation is accompanied by significant haem oxidation. Modification of one or two lysyl residues per chain (corresponding to approximately 20% of the total residues) does not affect the structural and functional properties of both haemoglobins, in line with the proposal that the intersubunit contacts are rich in hydrophobic residues. The modification of the thiol groups does not influence the state of association in both HbI and HbII, despite the location of the cysteine residue common to all polypeptide chains in the vicinity of the major intersubunit contact. The effect on the functional properties depends on the size of the thiol reagent: p-chloromercuribenzoate and phenylmercuric acetate increase the oxygen affinity about 20-fold, but iodoacetamide and mercuric chloride have no effect. Moreover, electrophoresis experiments indicate that p-chloromercuribenzoate is bound in a co-operative fashion, the degree of co-operativity being much higher in the dimeric HbI. Thus, only in HbII are intermediates containing substoichiometric amounts of p-chloromercuribenzoate formed in significant amounts. Their oxygen binding properties show that reaction of only one thiol group/tetramer suffices to alter the oxygen affinity of the molecule.

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Section: Modification Of Amino Groupssupporting

confidence: 69%

Structural and functional effects of selective chemical modifications of Scapharca inaequivalvis haemoglobins in relation to their unique assembly

Boffi¹,

Gattoni²,

Santucci³

et al. 1987

Biochemical Journal

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“…Acetylated Hemoglobin and Myoglobin. It has been shown by Bucci et al (1963) that acetylation of hemoglobin causes it to dissociate into dimers, in which form it is stable over a wide range of concentration. Acetylation, therefore, appeared to offer an ideal test of the relationship between degree of aggregation and quantum yields.…”

Section: Resultsmentioning

confidence: 99%

“…Acetylation of human hemoglobin and horse myoglobin was carried out following the procedure reported by Bucci et al (1963). The extent of acetylation for both proteins was about 70%, as measured by the ninhydrin reaction (Moore and Stein, 1948).…”

Section: Methodsmentioning

confidence: 99%

Studies on the Quantum Yields of the Photodissociation of Carbon Monoxide from Hemoglobin and Myoglobin^*

Noble¹,

Brunori²,

Wyman³

et al. 1967

Biochemistry

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The photodissociation of carbon monoxide ent, even for monomeric proteins, on ionic strength, from normal and modified myoglobin, hemoglobin protein concentration, and primary structure. It has subunits, and hemoglobin has been studied. The not been possible to establish definitely whether or not quantum yield of this process was found to be depend-protein aggregation state can influence quantum yield.

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“…These changes, in principle, depend on two kinds of causes, chemical and stereochemical, both of them arising as a consequence of the linking of the protein to the matrix [l]. Acetylation at alkaline pH of human oxyhemoglobin is accompanied by an increase in oxygen affinity, a decrease in the magnitude of the Bohr effect and a decrease in the value of n, which becomes pH dependent; these effects are more evident as the extent of the chemical modification increases [14]. Even though the functional properties of hemoglobin may depend upon the nature of the newly introduced group, it is reasonable to believe that, at least in part, changes in the oxygen equilibrium of the insoluble protein is due to the chemical modification of the amino groups.…”

Section: Discussionmentioning

confidence: 99%

Properties ofHuman Hemoglobin Immobilized on Sepharose 4B

Fanelli

Amiconi

Antonini

1978

European Journal of Biochemistry

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This paper reports the properties of human hemoglobin covalently bound to Sepharose 4B both in 'high-affinity' and 'low-affinity' conformations.The results suggest that the coupling reaction is strongly affected by the conformational changes linked to oxygenation of the protein. The rate and the extent of the reaction are different for the oxy and deoxyderivatives, probably due to the change in reactivity of the amino groups in the liganded and unliganded tetramer.The data on the equilibrium which is established between matrix-bound and soluble subunits, measured by the 'subunit-exchange chromatography', indicate that the system displays a minimal heterogeneity when hemoglobin is coupled to the gel in the deoxy state at intermediate protein concentration and pH 8.Matrix-bound hemoglobin is characterized by a higher oxygen affinity and by decreased homotropic and heterotropic interactions with respect to hemoglobin in solution, but the changes depend strongly on the conditions used in the coupling procedure.

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Studies on acetylated human hemoglobin

Cited by 22 publications

References 11 publications

Structural and functional effects of selective chemical modifications of Scapharca inaequivalvis haemoglobins in relation to their unique assembly

Structural and functional effects of selective chemical modifications of Scapharca inaequivalvis haemoglobins in relation to their unique assembly

Studies on the Quantum Yields of the Photodissociation of Carbon Monoxide from Hemoglobin and Myoglobin^*

Properties ofHuman Hemoglobin Immobilized on Sepharose 4B

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Studies on acetylated human hemoglobin

Cited by 22 publications

References 11 publications

Structural and functional effects of selective chemical modifications of Scapharca inaequivalvis haemoglobins in relation to their unique assembly

Structural and functional effects of selective chemical modifications of Scapharca inaequivalvis haemoglobins in relation to their unique assembly

Studies on the Quantum Yields of the Photodissociation of Carbon Monoxide from Hemoglobin and Myoglobin*

Properties ofHuman Hemoglobin Immobilized on Sepharose 4B

Contact Info

Product

Resources

About

Studies on the Quantum Yields of the Photodissociation of Carbon Monoxide from Hemoglobin and Myoglobin^*