The protonated form of 1-N6-etheno-[erythro-9-(2-hydroxy-3-nonyl)] adenine is identified at the active site of adenosine deaminase

Valeria R. Caiolfa, David Gill, Abraham H. Parola

Research output: Contribution to journalArticlepeer-review

Abstract

A novel fluorescent competitive inhibitor of adenosine deaminase (EC 3.5.4.4) (ADA), 1-N6-etheno-[erythro-9-(2-hydroxy-3-nonyl)] adenine (ε{lunate}-EHNA), is protonated at the active site of the enzyme. In ε{lunate}-EHNA [K1 = (4.06 ± 1.00) 10-6 M] part of the competive inhibition of EHNA is combined with spectroscopic properties of etheno-adenines. Computer subtraction of the fluorescence excitation spectrum of ADA from that of its equimolar complex with ε{lunate}-EHNA yielded the corrected excitation spectrum of ε{lunate}-EHNA at the active site of the enzyme. This spectrum mimics that of ε{lunate}-EHNA at pH 5.5 in buffer solution and is suggested to indicate a shift in protonation equilibrium at the active site.

Original languageEnglish
Pages (from-to)19-22
Number of pages4
JournalFEBS Letters
Volume260
Issue number1
DOIs
Publication statusPublished - Jan 15 1990

Keywords

  • 1-N-Etheno-[erythro-9-(2-hydroxy-3-nonyl)] adenine
  • Adenosine deaminase
  • Etheno-adenine
  • Fluorescence polarization
  • Fluorescent inhibitor
  • pH indicator

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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