Differential effects of 2,3-DPG, ATP and inositol pentaphosphate (IP5) on the oxygen equilibria of duck embryonic, fetal and adult hemoglobins

Borgese, Thomas A.; Nagel, Ronald L.

doi:10.1016/0300-9629(77)90282-1

Cited by 21 publications

(8 citation statements)

References 10 publications

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“…Both isoforms show O 2 affinities within the range reported previously for stripped Hbs of Emydidae (P 50 ϭ 1.9 -10.7 mmHg at pH 8 and 20°C) (42), and they appear to be similar to those of reptilian Hbs investigated so far (32). The higher O 2 affinity of HbD relative to HbA is consistent with the reported functional differences between the same isoHbs in birds (5,14). A previous study (8) also suggested coexpression of isoHbs in isolated intact red blood cells of T. scripta.…”

Section: Discussionsupporting

confidence: 90%

“…ATP had a much stronger inhibitory effect on Hb-O 2 affinity compared with Cl Ϫ (as apparent binding constants for the two anions differ by three orders of magnitude), indicating that ATP binding results in better stabilization of the lowaffinity T state. In contrast to bird Hbs, where HbA shows a stronger response to the allosteric cofactors ATP, IHP, and DPG (5,14,27,47), turtle HbD shows a higher affinity for ATP compared with HbA (Fig. 2).…”

Section: Discussionmentioning

confidence: 56%

“…Although the duplicative origins of the ␣ A -and ␣ D -globin genes vastly predate the divergence of extant sauropsid lineages, surprisingly consistent differences in the O 2 -binding properties of HbA and HbD have been maintained in birds and turtles (5,14,35,53). Interestingly, this consistent difference in O 2 affinity between the two isoHbs has persisted in spite of evolutionary changes in the relative sensitivity of HbA and HbD to different allosteric effectors.…”

Section: Discussionmentioning

confidence: 91%

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Hemoglobin isoform differentiation and allosteric regulation of oxygen binding in the turtle,Trachemys scripta

Damsgaard

Storz

Hoffmann

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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When freshwater turtles acclimatize to winter hibernation, there is a gradual transition from aerobic to anaerobic metabolism, which may require adjustments of blood O2 transport before turtles become anoxic. Here, we report the effects of protons, anionic cofactors, and temperature on the O2-binding properties of isolated hemoglobin (Hb) isoforms, HbA and HbD, in the turtle Trachemys scripta. We determined the primary structures of the constituent subunits of the two Hb isoforms, and we related the measured functional properties to differences in O2 affinity between untreated hemolysates from turtles that were acclimated to normoxia and anoxia. Our data show that HbD has a consistently higher O2 affinity compared with HbA, whereas Bohr and temperature effects, as well as thiol reactivity, are similar. Although sequence data show amino acid substitutions at two known β-chain ATP-binding site positions, we find high ATP affinities for both Hb isoforms, suggesting an alternative and stronger binding site for ATP. The high ATP affinities indicate that, although ATP levels decrease in red blood cells of turtles acclimating to anoxia, the O2 affinity would remain largely unchanged, as confirmed by O2-binding measurements of untreated hemolysates from normoxic and anoxic turtles. Thus, the increase in blood-O2 affinity that accompanies winter acclimation is mainly attributable to a decrease in temperature rather than in concentrations of organic phosphates. This is the first extensive study on freshwater turtle Hb isoforms, providing molecular evidence for adaptive changes in O2 transport associated with acclimation to severe hypoxia.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 91%

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Hemoglobin isoform differentiation and allosteric regulation of oxygen binding in the turtle,Trachemys scripta

Damsgaard

Storz

Hoffmann

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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“…In some taxa, developmental changes in blood-oxygen affinity are at least partly attributable to the stagespecific expression of functionally distinct isoHbs. This Hb switching has been documented in a number of birds (Borgese and Nagel, 1977;Baumann et al, 1982), crocodilians (Grigg et al, 1993), snakes (Pough, 1977;Birchard et al, 1984;Ragsdale and Ingermann, 1991) and turtles (Wells and Baldwin, 1994). In some taxa, such as the viviparous lizard, Sphenomorphus quoyii (Grigg and Harlow, 1981), developmental changes in blood-oxygen affinity are primarily attributable to changes in the red cell concentrations of organic phosphates or other allosteric cofactors that modulate Hb-oxygen affinity.…”

Section: Discussionmentioning

confidence: 75%

Developmental regulation of hemoglobin synthesis in the green anole lizard Anolis carolinensis

Storz

Hoffmann

Opazo

et al. 2011

Journal of Experimental Biology

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SUMMARYTetrapod vertebrates possess multiple -and -like globin genes that are ontogenetically regulated, such that functionally distinct hemoglobin (Hb) isoforms are synthesized during different stages of development. The -and -like globin genes of amphibians, birds and mammals are differentially expressed during embryonic development and postnatal life, but little is known about the developmental regulation of globin gene expression in non-avian reptiles. Here we report an investigation into the developmental regulation of Hb synthesis in the green anole lizard Anolis carolinensis. We tested two hypotheses derived from comparative genomic studies of the globin gene clusters in tetrapod vertebrates. First, we tested whether the product of the Anolis  D -globin gene is incorporated into embryonic Hb, thereby performing the role that would normally be performed by the embyronic  E -globin gene (which has been deleted from the green anole genome). Second, we tested whether two 'lizard-specific' -globin paralogs have independently evolved a division of labor between an early-expressed embryonic gene and a later-expressed adult gene. Results of a proteomic analysis revealed that -and -like globin genes of the anole are differentially expressed during embryonic development. However, the same repertoire of -and -chain Hb isoforms was expressed during all stages of development and postnatal life, and the ontogenetic shifts in isoform composition were relatively subtle. In contrast to the pattern that has been documented in other tetrapod vertebrates, it appears that the developmental regulation of Hb synthesis in the green anole lizard does not involve discrete, stage-specific switches in gene activation and gene silencing.

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“…It is now recognized that the naturally occurring form of inositol polyphosphate in the erythrocytes of most mature species of birds is actually inositol pentaphosphate (Section 2). This latter compound is effective in causing a right shift of the oxygen equilibrium of fetal-and adult-type duck hemoglobins (Borgese and Nagel, 1977). Borgese and Nagel (1978) recently reported that inositol pentaphosphate is also present in the red cells of two species of elasmobranch fish and suggested that it may play a role in regulating the oxygen affinity of dogfish and torpedo hemoglobins.…”

Section: Function Of Inositol Phosphatesmentioning

confidence: 97%

The Nutritional Significance, Metabolism, and Function of myo-Inositol and Phosphatidylinositol in Health and Disease

Holub

1982

Advances in Nutritional Research

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Differential effects of 2,3-DPG, ATP and inositol pentaphosphate (IP5) on the oxygen equilibria of duck embryonic, fetal and adult hemoglobins

Cited by 21 publications

References 10 publications

Hemoglobin isoform differentiation and allosteric regulation of oxygen binding in the turtle,Trachemys scripta

Hemoglobin isoform differentiation and allosteric regulation of oxygen binding in the turtle,Trachemys scripta

Developmental regulation of hemoglobin synthesis in the green anole lizard Anolis carolinensis

The Nutritional Significance, Metabolism, and Function of myo-Inositol and Phosphatidylinositol in Health and Disease

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