Classical isolation procedure for plasma membrane H(+)-ATPase of Saccharomyces cerevisiae based on fractional centrifugation yielded always a roughly two-fold greater amount of membranes when starting from glucitol-preincubated than from glucose-preincubated yeast. This difference persisted all the way to the purified plasma membranes and to the purified H(+)-ATPase. The ATP-hydrolyzing activity by plasma membranes was roughly twice greater in glucose-preincubated cells than in the D-glucitol-preincubated ones while the purified enzyme was 7 times more active after glucose than after glucitol. Effects of diethylstilbestrol, suloctidil, erythrosin B, vanadate and dicarbanonaboranuide were very similar on plasma membrane-localized and purified ATPases of both forms, suggesting that both preparations contain the two ATPase forms, the glucose-preincubated one being richer in the activated form while the glucitol-preincubated one contains less of it.

• MeSH
• adenosintrifosfát metabolismus   MeSH
• buněčná membrána enzymologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• kultivační média MeSH
• protonové ATPasy antagonisté a inhibitory   izolace a purifikace   metabolismus   MeSH
• Saccharomyces cerevisiae enzymologie   růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosintrifosfát MeSH
• inhibitory enzymů MeSH
• kultivační média MeSH
• protonové ATPasy MeSH

The process of acidification of the external medium after addition of glucose and subsequently of KCl to a suspension of yeast cells varies substantially from species to species. After glucose it is most pronounced in Saccharomyces cerevisiae and Schizosaccharomyces pombe but is very much lower in Lodderomyces elongisporus, Dipodascus magnusii and Rhodotorula gracilis. Both the buffering capacity and the varied effects of vanadate, suloctidil and erythrosin B indicate that the acidification is by about one-half due to the activity of plasma membrane H(+)-ATPase and by about one-half to the extrusion of acidic metabolites from cells. This is supported by the finding that a respiratory quotient greater than one (in various strains of S. cerevisiae and in S. pombe) is indicative of a greater buffering capacity and overall acidification of the medium. Taking into account the virtually negligible buffering capacity of the medium in the pH range where the effect of K+ is observed, the effect of K+ is generally of a similar magnitude as that of adding glucose. It is clearly dependent on (anaerobic) production of metabolic energy, quite distinct from the dependence of the H(+)-ATPase-caused acidification.

• MeSH
• biologický transport MeSH
• draslík farmakologie   MeSH
• erythrosin farmakologie   MeSH
• glukosa farmakologie   MeSH
• kationty jednomocné farmakologie   MeSH
• kyseliny metabolismus   MeSH
• protonové ATPasy metabolismus   MeSH
• Saccharomycetales účinky léků   metabolismus   MeSH
• spotřeba kyslíku MeSH
• suloktidil farmakologie   MeSH
• vanadáty farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• draslík MeSH
• erythrosin MeSH
• glukosa MeSH
• kationty jednomocné MeSH
• kyseliny MeSH
• protonové ATPasy MeSH
• suloktidil MeSH
• vanadáty MeSH

Acidification of the external medium of the yeast Saccharomyces cerevisiae, mainly caused by proton extrusion by plasma membrane H(+)-ATPase, was inhibited to different degrees by D2O, diethylstilbestrol, suloctidil, vanadate, erythrosin B, cupric sulfate and dicyclohexylcarbodiimide. The same pattern of inhibition was found with the uptake of amino acids, adenine, uracil, and phosphate and sulfate anions. An increase of the acidification rate by dioctanoylglycerol also increased the rates of uptake of adenine and of glutamic acid. In contrast, a decrease of the membrane potential at pH 4.5 from a mean of -40 to -20 mV caused by 20 mM KCl had no effect on the transport rates. The ATPase-deficient mutant S. cerevisiae pmal-105 showed a markedly lower uptake of all the above solutes as compared with the wild type, while its membrane potential and delta pH were unchanged. Other types of acidification (spontaneous upon suspension; K+ stimulated) did not affect the secondary uptake systems. A partially competitive inhibition between some individual transport systems was observed, most pronouncedly with adenine as the most avidly transported solute. These observations, together with the earlier results that inhibition of H(+)-ATPase activity affects more the acidic than the basic amino acids and that it is more pronounced at higher pH values and at greater solute concentrations, support the view that it is the protons in or at the membrane, as they are extruded by the ATPase, that govern the rates of uptake by secondary active transport systems in yeast.

• MeSH
• aktivní transport MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• membránové potenciály MeSH
• protonové ATPasy antagonisté a inhibitory   metabolismus   MeSH
• Saccharomyces cerevisiae enzymologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protonové ATPasy MeSH