Reactivity differences between haemoglobins. Part XVI. A correlation between the amino-acid composition of methaemoglobins and their reactivity towards azide ion
- 1 January 1970
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc. A
- p. 749-756
- https://doi.org/10.1039/j19700000749
Abstract
The standard free-energies and enthalpies of formation of the azide complex of three human abnormal methaemoglobins, human fetal methaemoglobin FII, and five animal methaemoglobins have been determined as a function of pH. For all the methaemoglobins –ΔH° passes through a maximum at a pH, pHch, characteristic of the particular methaemoglobin. There is a correlation between pHch and a simple function of the number of lysine, arginine, glutamic acid, and aspartic acid residues in the molecules. The pK values of ionization of methaemoglobins FII, DIbadan, and NBaltimore have been determined as a function of temperature and ionic strength. The variation of pK with ionic strength and the difference between the values of the pK values at zero ionic strength are shown to be consistent with the dielectric cavity model for the protein used in earlier papers in the series.Keywords
This publication has 0 references indexed in Scilit: