Fluorescence studies on the binding of reduced nicotinamide adenine dinucleotide phosphate to human hemoglobin A and its variant hemoglobin Providence.

Published

Journal Article

The affinity constants for the binding of NADPH to human hemoglobin A were directly determined by fluorescence analysis since nucleotide fluorescence is quenched on binding to the protein. The binding constants 6.1 x 10(5), 5.02 x 10(5) and 1.2 x 10(5) were found for deoxyhemoglobin at pH 6.5, 7.0 and 7.5, respectively. Oxyhemoglobin does not bind NADPH significantly. These results are consistent with those found in oxygen-hemoglobin equilibrium experiments. The human hemoglobin variant, Providence-Asp, which has a marked decrease in 2,3 DPG affinity was also investigated. NADPH does not bind to the variant suggesting that the Lys B 82 residue is of fundamental importance to nucleotide binding and showing that the binding site is the same as that of 2,3 DPG or other organic polyphosphate, allosteric modulators of hemoglobins. Experiments of inositol hexaphosphate (IHP)-NADPH site competition corroborate these results.

Full Text

Duke Authors

Cited Authors

  • Ogo, SH; Focesi Júnior, A; Cashon, R; Bonaventura, C; Bonaventura, J

Published Date

  • January 1987

Published In

Volume / Issue

  • 20 / 6

Start / End Page

  • 755 - 758

PubMed ID

  • 3455253

Pubmed Central ID

  • 3455253

Electronic International Standard Serial Number (EISSN)

  • 1414-431X

International Standard Serial Number (ISSN)

  • 0100-879X

Language

  • eng