In vivo analysis of Saccharomyces cerevisiae plasma membrane ATPase Pma1p isoforms with increased in vitro H+/ATP stoichiometry

Plasma membrane H⁺-ATPase isoforms with increased H⁺/ATP ratios represent a desirable asset in yeast metabolic engineering. In vivo proton coupling of two previously reported Pma1p isoforms (Ser800Ala, Glu803Gln) with increased in vitro H⁺/ATP stoichiometries was analysed by measuring biomass yields of anaerobic maltose-limited chemostat cultures expressing only the different PMA1 alleles. In vivo H⁺/ATP stoichiometries of wildtype Pma1p and the two isoforms did not differ significantly.