Electric charge distribution in proteins and ionic strength dependence of reaction rate

Tsuyoshi Egawa, Takahiro Masuda

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The ionic strength dependence of the reaction rate between protein and dichloride anion radical has been investigated by flash photolysis of aqueous chloride-containing lysozyme, ribonuclease A, or insulin. The rate constant for the reaction of lysozyme or ribonuclease A with dichloride anion radicals decreases with increasing ionic strength, while it increases for insulin. The dependence was found to obey an equation derived from the theory of Debye and Hückel or the equation of Wherland and Gray for lysozyme within experimental errors. For ribonuclease A, however, it deviates largely from these equations. In the case of insulin a moderate deviation was observed. The different behavior in the ionic strength dependence is discussed in terms of the electric charge distribution in the protein molecules.

Original languageEnglish (US)
Pages (from-to)207-213
Number of pages7
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number3
StatePublished - May 1 1989


  • Anion radical
  • Electric charge distribution
  • Flash photolysis
  • Ionic strength dependence
  • Reaction rate

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology


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