Modification of the red beet plasma membrane H+-ATPase by diethylpyrocarbonate

Lynne H. Gildensoph, Donald P. Briskin

Research output: Contribution to journalArticle

Abstract

Incubation of the red beet (Beta vulgaris L.) plasma membrane H+-ATPase with micromolar concentrations of diethylpyrocarbonate (DEPC) resulted in inhibition of both ATP hydrolytic and proton pumping activity. Enzyme activity was restored when DEPC-modified protein was incubated with hydroxylamine, suggesting specific modification of histidine residues. Kinetic analyses of DEPC inhibition performed on both membrane-bound and solubilized enzyme preparations suggested the presence of at least one essential histidine moiety per active site. Inclusion of either ATP (substrate) or ADP (product and competitive inhibitor) in the modification medium reduced the amount of inhibition observed in the presence of DEPC. However, protection was not entirely effective in returning activity to noninhibited control values. These results suggest that the modified histidine does not reside directly in the ATP binding region of the enzyme, but is more likely involved in enzyme regulation through subtle conformational effects.

Original languageEnglish (US)
Pages (from-to)696-703
Number of pages8
JournalPlant physiology
Volume94
Issue number2
DOIs
StatePublished - Oct 1990

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

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