Bilirubin acidity. Titrimetric and 13C NMR studies.

@article{Hansen1979BilirubinAT,
  title={Bilirubin acidity. Titrimetric and 13C NMR studies.},
  author={Poul Erik Hansen and H. A. Thiessen and R. Marc Brodersen},
  journal={Acta chemica Scandinavica. Series B: Organic chemistry and biochemistry},
  year={1979},
  volume={33 4},
  pages={281-93}
}
Acidimetric titration of bilirubin IX-alpha, dissolved in excess aqueous sodium hydroxide, showed that two protons are dissociated with pK values well below 7 and that one or several additional acidic groups titrate with pK around 12.9. Precipitation of the nearly insoluble acid precluded determination of the two lower pK values by titration in aqueous solution. In dimethyl sulfoxide solution, four acidic protons were demonstrated, titrating two by two without precipitation. 13C NMR spectra of… CONTINUE READING