Enzymatic properties of the PMA2 plasma membrane-bound H(+)-ATPase of Saccharomyces cerevisiae

J Biol Chem. 1993 Sep 15;268(26):19753-9.

Abstract

The PMA1 H(+)-ATPase can be functionally replaced by its isoform PMA2 in the plasma membrane from Saccharomyces cerevisiae (Supply, P., Wach, A., Thinès-Sempoux, D., and Goffeau, A. (1993) J. Biol. Chem. 268, 19744-19752). From strains expressing either only PMA1 or PMA2, plasma membranes were isolated and their ATPase activities compared. Despite their 89% identity, the two enzymes differ as to the following parameters: activation by glucose and by Triton X-100, pH optimum, requirement for divalent cations, and inhibition by vanadate and by erythrosin B. More striking, the glucose-activated PMA2 enzyme displays a three to four times higher apparent affinity for MgATP, and maximal activity is reached with a 10-fold lower free Mg2+ concentration. These results suggest that the difference in PMA1 and PMA2 expression level is correlated with different H(+)-ATPase functions. The analysis of the PMA1 and PMA2 sequence alignment, compared with reported PMA1 mutations, points to a few residue substitutions as putative contributors to the observed kinetic changes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cell Membrane / enzymology
  • Detergents / pharmacology
  • Erythrosine / pharmacology
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Kinetics
  • Magnesium / pharmacology
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Octoxynol
  • Polyethylene Glycols / pharmacology
  • Proton-Translocating ATPases / genetics
  • Proton-Translocating ATPases / metabolism*
  • Regression Analysis
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Sequence Homology, Amino Acid
  • Sorbitol / pharmacology
  • Thermodynamics
  • Vanadates / pharmacology

Substances

  • Detergents
  • Isoenzymes
  • Vanadates
  • Polyethylene Glycols
  • Sorbitol
  • Octoxynol
  • Proton-Translocating ATPases
  • Magnesium
  • Erythrosine