Enzymatic-properties of the Pma2 Plasma Membrane-bound H+-atpase of Saccharomyces-cerevisiae
(1993) Journal of Biological Chemistry — Vol. 268, n° 26, p. 19753-19759 (1993)
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- Abstract
- The PMA1 H+-ATPase can be functionally replaced by its isoform PMA2 in the plasma membrane from Saccharomyces cerevisiae (Supply, P., Wach, A., Thines-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.
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Supply, P., Wach, A., & Goffeau, A. (1993). Enzymatic-properties of the Pma2 Plasma Membrane-bound H+-atpase of Saccharomyces-cerevisiae. Journal of Biological Chemistry, 268(26), 19753-19759. https://hdl.handle.net/2078.5/44363 (Original work published 1993)