Preparation and properties of the isolated α and β chains of human hemoglobin in the ferri state

Banerjee, R.; Cassoly, Robert

doi:10.1016/0022-2836(69)90047-3

Cited by 59 publications

(22 citation statements)

References 16 publications

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“…This result indicates that reduction does not dissociate the AHSP⅐␣ complex at the micromolar protein concentrations used in the measurements, as predicted from previous measurements of the K D for binding of the ferric (0.0006 M) and ferrous (0.017 M) forms of ␣ to AHSP (17). E 1 ⁄2 o values measured for isolated ␤-subunits were variable and differed substantially from those reported by other groups (42,43). Although the reason for this is unclear, we found that irreversible ␤-subunit denaturation during our experiments prevented reliable measurement.…”

Section: Resultssupporting

confidence: 69%

“…Also, ␤-subunits readily self-associate into homotetramers (45). Neither our experiments nor those of Abraham and Taylor (42) or Banerjee and Cassoly (43) adequately controlled for this phenomenon.…”

Section: Resultscontrasting

confidence: 66%

“…Midpoint Redox Potential-The redox potentials of isolated HbA subunits have previously been investigated by two groups using potentiometric methods (42,43). Neither group reported the effects of AHSP binding to ␣-subunits on midpoint potential.…”

Section: Resultsmentioning

confidence: 99%

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α-Hemoglobin Stabilizing Protein (AHSP) Markedly Decreases the Redox Potential and Reactivity of α-Subunits of Human HbA with Hydrogen Peroxide

Mollan

Banerjee

et al. 2013

Journal of Biological Chemistry

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Background: ␣-Hemoglobin stabilizing protein (AHSP) modifies the redox properties of bound ␣-subunits. Results: Isolated hemoglobin subunits exhibit significantly different redox properties compared with HbA. A significant decrease in the reduction potential of ␣-subunits bound to AHSP results in preferential binding of ferric ␣. Conclusion: AHSP⅐␣-subunit complexes do not participate in ferric-ferryl heme redox cycling. Significance: AHSP binding to ␣-subunits inhibits subunit pseudoperoxidase activity.

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Section: Resultssupporting

confidence: 69%

Section: Resultscontrasting

confidence: 66%

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α-Hemoglobin Stabilizing Protein (AHSP) Markedly Decreases the Redox Potential and Reactivity of α-Subunits of Human HbA with Hydrogen Peroxide

Mollan

Banerjee

et al. 2013

Journal of Biological Chemistry

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“…4. This paradigm, in which met-Hb plays a significant role, is based on results reported herein for SH-modified forms of Hb A 0 (NEM-Hb A 0 , PDS-Hb A 0 , and SNO-Hb A 0 ), and CPA-Hb (SNO-CPA-Hb), as well as reports from the literature (3,6,17,36,42,48). Possible responses to low oxygen conditions are shown, although the physiological condition is rarely "free" of oxygen, and met-Hb levels are usually low.…”

Section: Discussionmentioning

confidence: 69%

Heme Redox Properties of S-Nitrosated Hemoglobin A0 and Hemoglobin S

Bonaventura¹,

Taboy²,

Low³

et al. 2002

Journal of Biological Chemistry

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S-NitrosatedThe reactivity of heme proteins with nitro and nitroso compounds has been under intense scrutiny since Ignarro et al. (1,2) reported the ability of some of these compounds to activate an ␣␤ heterodimer enzyme containing a b-type heme, sGC, involved in the relaxation of the endothelium (3, 4). Nitric oxide (NO) has been observed to react with Fe-porphyrin complexes in various oxidation states (Fe . Reaction of NO with oxygenated heme groups results in heme oxidation and nitrate formation. This process, like NO binding to deoxy-Hb, occurs rapidly and with a similar rate constant (10 -12). As shown in this report, reactions of NO at the sulfhydryl groups of Hb also promote met-Hb formation. Several lines of study have shown that S-nitrosated Hb (SNO-Hb) can be formed in vivo and in vitro, and although present at low concentration, may be of importance in blood pressure regulation. Hb contains a highly conserved cysteine residue at position ␤93 whose reactions with NO may account for its persistence in hemoglobin's evolutionary history. A dynamic cycle of SNO-Hb formation in the lungs and NO release in the tissues was implicated by finding the presence of greater levels of SNO-Hb in aortic relative to venous blood (13). This cycle has, however, been brought into question. Notably, Gladwin and co-workers (14) did not see higher levels of SNO-Hb in aortic blood, even in patients given low levels of NO in breathing gas (4 M NO delivered to 10 mM heme).It is now well established that the formation of SNO-Hb is under allosteric control (13). Functional and crystallographic studies demonstrate that the ␤Cys 93 residues at which NO is bound in SNO-Hb A 0 are more accessible in the high affinity conformation of oxy (R-state) Hb than in deoxy (T-state) Hb (6,15,16). This conformational sensitivity results in a rate dependence for SNO-Hb formation that mirrors the greater relative exposure of ␤Cys 93 in conditions that favor the R-state. Allosteric considerations were also invoked to explain the decreased stability of the deoxy form of SNO-Hb (13), but allosteric control of NO release from SNO-Hb in vivo is still under debate (14,17,18). In a purified condition, free of red blood cell constituents, SNO-Hb is sufficiently stable to allow oxygen binding studies (7) and oxidation-reduction studies (this report) to be carried out over a period of several hours without significant loss of NO from the SNO-Hb derivative.Stamler and co-workers (19) recently presented evidence showing that interactions of SNO-Hb with the Band 3 protein on the erythrocyte membrane can facilitate NO release from * This work was supported by the National Institutes of Health Grants RO1 HL-58248, 1R43 HL-6586, and GM24417, NIEHS Center Grant ESO-1908, and the North Carolina Biotechnology Center through financial support of the Duke University Mass Spectrometry Facility. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with ...

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“…The supernatant at pH 6.6, which was passed through Sephadex G-25 column equilibrated with 10 mM potassium phosphate buffer (pH 6.8), was applied on a CM Sephadex C-50 column and eluted with pH gradient phosphate buffer made up from 10 mM potassium phosphate (pH 6.8) and 20 mM K2HPO4 as in [3]. The effluent containing the intermediate hemoglobin was rechromatographed by the same procedure.…”

Section: Methodsmentioning

confidence: 99%