Isotope-coded, iodoacetamide-based reagent to determine individual cysteine pK(a) values by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

@article{Nelson2008IsotopecodedIR,
  title={Isotope-coded, iodoacetamide-based reagent to determine individual cysteine pK(a) values by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.},
  author={Kimberly J. Nelson and Amanda E Day and Bu-Bing Zeng and S Bruce King and Leslie B. Poole},
  journal={Analytical biochemistry},
  year={2008},
  volume={375 2},
  pages={187-95}
}
Cysteine reactivity in enzymes is imparted to a large extent by the stabilization of the deprotonated form of the reduced cysteine (i.e., the thiolate) within the active site. Although this is likely to be an important chemical attribute of many thiol-based enzymes, including cysteine-dependent peroxidases (peroxiredoxins) and proteases, only relatively few pK(a) values have been determined experimentally. Presented here is a new technique for determining the pK(a) value of cysteine residues… CONTINUE READING