The Hemoglobins

Kleihauer, E.

doi:10.1007/978-1-4684-2316-7_11

Cited by 4 publications

(3 citation statements)

References 162 publications

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“…The amounts of the various hemoglobins present from the very early embryonic period through the fetal stage and into adulthood (ontogeny) have been reported by several investigators, including Huehns et al (1964c), Huehns and Shooter (1965), and Kleihauer (1970). Embryonic, fetal, and adult hemoglobins attain their highest concentrations at different times during development (Fig.…”

Section: Discussionmentioning

confidence: 95%

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Human embryonic, fetal, and adult hemoglobins have different subunit interface strengths. Correlation with lifespan in the red cell

et al. 2007

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The different types of naturally occurring, normal human hemoglobins vary in their tetramer-dimer subunit interface strengths (stabilities) by three orders of magnitude in the liganded (CO or oxy) state. The presence of embryonic z-subunits leads to an average 20-fold weakening of tetramer-dimer interfaces compared to corresponding hemoglobins containing adult a-subunits. The dimer-monomer interfaces of these hemoglobins differ by at least 500-fold in their strengths; such interfaces are weak if they contain z-subunits and exchange with added b-subunits in the form of b 4 (HbH) significantly faster than do those with a-subunits. Subunit exchange occurs at the level of the dimer, although tetramer formation reciprocally influences the amount of dimer available for exchange. Competition between subunit types occurs so that pairs of weak embryonic hemoglobins can exchange subunits to form the stronger fetal and adult hemoglobins. The dimer strengths increase in the order Hb Portland-2 (z 2 b 2 ) < Hb Portland-1 (z 2 g 2 ) ffi Hb Gower-1 (z 2 e 2 ) < Hb Gower-2 (a 2 e 2 ) < HbF 1 < HbF (a 2 g 2 ) < HbA 2 (a 2 d 2 ), i.e., from embryonic to fetal to adult types, representing maturation from weaker to stronger monomermonomer subunit contacts. This increasing order recapitulates the developmental order in which globins are expressed (embryonic ! fetal ! adult), suggesting that the intrinsic binding properties of the subunits themselves regarding the strengths of interfaces they form with competing subunits play an important role in the dynamics of protein assemblies and networks.

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Section: Discussionmentioning

confidence: 95%

“… Normal developmental profile of hemoglobins. Data are from Huehns and Shooter (1965) and from Kleihauer (1970) as rendered by Bunn and Forget (1986). The names of the normal embryonic hemoglobins are Gower‐1 (ζ 2 ε 2 ), Gower‐2 (α 2 ε 2 ), and Portland‐1 (ζ 2 γ 2 ).…”

mentioning

confidence: 99%

Human embryonic, fetal, and adult hemoglobins have different subunit interface strengths. Correlation with lifespan in the red cell

et al. 2007

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“…Fetal Hb (HbF, α 2 γ 2 ) is the least dissociated of all the human Hbs (Fig. 4C, blue curve), consistent with the rapid onset of its synthesis at 6 weeks [25,26], owing to its very low free energy as calculated from its dissociation constant [27]. Subsequently, slow post‐translational acetylation at the N‐terminus of its γ‐subunit (HbF 1 , α 2 γ 2 Ac ) weakens its very strong subunit interactions (Fig.…”

Section: Role Of Subunit Interfaces During Developmentmentioning

confidence: 55%

Intrinsic regulation of hemoglobin expression by variable subunit interface strengths

et al. 2011

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SUMMARY The expression of the six types of human hemoglobin subunits over time is currently considered to be regulated mainly by transcription factors that bind to upstream control regions of the gene (the “extrinsic” component of regulation). Here we describe how subunit pairing and further assembly to tetramers in the liganded state is influenced by the affinity of subunits for one another (the “intrinsic” component of regulation). The adult hemoglobin dimers have the strongest subunit interfaces and the embryonic hemoglobins are the weakest with fetal hemoglobins of intermediate strength, corresponding to the temporal order of their expression. These variable subunit binding strengths and the attenuating effects of acetylation contribute to the differences with which these hemoglobin types form functional O2-binding tetramers consistent with gene switching.

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Physiologische Prämissen: Hämoglobin, Sauerstoffsättigung, -transport und -verbrauch im Kindesalter

Kattner¹

1991

Kinderanästhesie

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The Hemoglobins

Cited by 4 publications

References 162 publications

Human embryonic, fetal, and adult hemoglobins have different subunit interface strengths. Correlation with lifespan in the red cell

Human embryonic, fetal, and adult hemoglobins have different subunit interface strengths. Correlation with lifespan in the red cell

Intrinsic regulation of hemoglobin expression by variable subunit interface strengths

Physiologische Prämissen: Hämoglobin, Sauerstoffsättigung, -transport und -verbrauch im Kindesalter

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