pH-induced bistable dynamic behaviour in the reaction catalysed by glucose-6-phosphate dehydrogenase and conformational hysteresis of the enzyme

M. A. Aon, S. Cortassa, J. F. Hervagault, D. Thomas

Research output: Contribution to journalArticlepeer-review

Abstract

Bistable (multiple stationary states) dynamic behaviour in the activity of glucose-6-phosphate dehydrogenase that was subjected to successive pH change was demonstrated in an open continuously stirred tank reactor. Although the enzyme under study did not exhibit an autocatalytic effect and was homogeneously distributed, bistability was shown to occur. The successive ph changes of the enzyme solution corresponded to a pH transition (8.3 ⇆ 2), i.e. an acidification (forward direction) and an alkalinization (reverse direction). By use of intrinsic protein fluorescence methods, a glucose-6-phosphate dehydrogenase conformational hysteresis was shown to exist concomitant with the pH transition before and after enzyme injection into the reactor. The results obtained suggest that the enzyme behaves, conformationally, as a memory device that stores information about its pH history (i.e. the enzyme records information in its structure about the environment to which it was previously exposed) and transduces it in a non-linear dynamic fashion, producing the bistable behaviour observed in the open reactor.

Original languageEnglish (US)
Pages (from-to)795-800
Number of pages6
JournalBiochemical Journal
Volume262
Issue number3
DOIs
StatePublished - 1989

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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