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The nicotinamide adenine dinucleotides as allosteric effectors of human hemoglobin.

Publication ,  Journal Article
Cashon, R; Bonaventura, C; Bonaventura, J; Focesi, A
Published in: The Journal of biological chemistry
September 1986

The oxygen binding properties of human hemoglobin are appreciably altered by the nicotinamide dinucleotides NADH, NADP+, and NADPH. These cofactors are important in the control of many metabolic pathways and in providing reductive potential for a number of enzymatic reactions, including in vivo reduction of methemoglobin. Specific binding of these cofactors to hemoglobin and their potential for acting as allosteric modifiers of hemoglobin function have not been previously recognized. Detailed oxygen binding studies utilizing a thin-layer method suggest that the nicotinamide dinucleotides bind with high affinity to the deoxyhemoglobin tetramer at the beta chain anion-binding site and stabilize the low affinity "T-state" conformation. Stripped Hb A in 0.05 M N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer, pH 6.5, at 20 degrees C is half-saturated at a pO2 of 1.6 mm Hg. In the presence of 0.5 mM NADH, NADP+, or NADPH, the P50 is raised to 3.8, 7.1, and 12.5 mm Hg, respectively. The Bohr factor for stripped Hb A in 0.05 M HEPES buffer is sensitive to these effectors and is raised from 0.25 to about 0.65 by the addition of NADPH. The data suggest that routine use of these effectors in studies of human hemoglobin variants or the allosteric mechanism of Hb A be considered carefully. The relatively low intraerythrocytic levels of the nicotinamide dinucleotides in relation to hemoglobin dictate that these cofactors cannot significantly affect in vivo oxygen delivery. However, the converse is theoretically possible. The binding of the cofactors to hemoglobin and the preferential binding of their reduced forms may affect cofactor-dependent metabolic processes in red blood cells.

Duke Scholars

Published In

The Journal of biological chemistry

DOI

EISSN

1083-351X

ISSN

0021-9258

Publication Date

September 1986

Volume

261

Issue

27

Start / End Page

12700 / 12705

Related Subject Headings

  • Protein Conformation
  • Oxyhemoglobins
  • Oxygen
  • NADP
  • NAD
  • Hydrogen-Ion Concentration
  • Hemoglobins
  • Hemoglobin A
  • Biochemistry & Molecular Biology
  • 34 Chemical sciences
 

Citation

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Cashon, R., Bonaventura, C., Bonaventura, J., & Focesi, A. (1986). The nicotinamide adenine dinucleotides as allosteric effectors of human hemoglobin. The Journal of Biological Chemistry, 261(27), 12700–12705. https://doi.org/10.1016/s0021-9258(18)67148-0
Cashon, R., C. Bonaventura, J. Bonaventura, and A. Focesi. “The nicotinamide adenine dinucleotides as allosteric effectors of human hemoglobin.The Journal of Biological Chemistry 261, no. 27 (September 1986): 12700–705. https://doi.org/10.1016/s0021-9258(18)67148-0.
Cashon R, Bonaventura C, Bonaventura J, Focesi A. The nicotinamide adenine dinucleotides as allosteric effectors of human hemoglobin. The Journal of biological chemistry. 1986 Sep;261(27):12700–5.
Cashon, R., et al. “The nicotinamide adenine dinucleotides as allosteric effectors of human hemoglobin.The Journal of Biological Chemistry, vol. 261, no. 27, Sept. 1986, pp. 12700–05. Epmc, doi:10.1016/s0021-9258(18)67148-0.
Cashon R, Bonaventura C, Bonaventura J, Focesi A. The nicotinamide adenine dinucleotides as allosteric effectors of human hemoglobin. The Journal of biological chemistry. 1986 Sep;261(27):12700–12705.

Published In

The Journal of biological chemistry

DOI

EISSN

1083-351X

ISSN

0021-9258

Publication Date

September 1986

Volume

261

Issue

27

Start / End Page

12700 / 12705

Related Subject Headings

  • Protein Conformation
  • Oxyhemoglobins
  • Oxygen
  • NADP
  • NAD
  • Hydrogen-Ion Concentration
  • Hemoglobins
  • Hemoglobin A
  • Biochemistry & Molecular Biology
  • 34 Chemical sciences