Tryptophan fluorescence quenching by alkaline pH and ternary complex formation in human β1β1 and horse EE alcohol dehydrogenases

Torsten Ehrig, Barry B. Muhoberac, Thomas D. Hurley, William F. Bosron

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

The horse EE and human β1β1 alcohol dehydrogenase isoenzymes have almost identical protein backbone folding patterns and contain 2 tryptophans per subunit (Trp-15 and Trp-314). Tyr-286, which had been proposed to quench the fluorescence of Trp-314 by resonance energy transfer at alkaline pH in EE, is substituted by Cys in β1β1. The proposed role of Tyr-286 in pH-dependent quenching of EE is confirmed by our observation that tryptophan fluorescence of β1β1 is not substantially quenched at alkaline pH. Tyr-286 had also been implicated in the quenching of Trp-314 upon formation of the EE-NAD+-trifluoroethanol ternary complex. However, β1β1 exhibits the same extent of tryptophan fluorescence quenching as EE upon complexation, which strongly suggests that Tyr-286 is not involved in ternary complex quenching.

Original languageEnglish (US)
Pages (from-to)283-285
Number of pages3
JournalFEBS Letters
Volume300
Issue number3
DOIs
StatePublished - Apr 6 1992

Keywords

  • Alcohol dehydrogenase
  • Fluorescence spectroscopy
  • Isoenzyme
  • Tryptophan quenching

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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