Titratable acidity of the extracellular medium was compared with that calculated from pH changes in a suspension of Saccharomyces cerevisiae. After addition of cells to normal water the ratio of titratable acidity to the computed one was about 25, after addition of 50 mmol/L D-glucose it was about 13, after subsequent addition of K+ ions it was only 2. In heavy water the respective values were 30, 9, and 1. Apparently, the principal buffer-generating processes have to do with glucose metabolism but little with the K+/H+ exchange observed after addition of K+. D2O appears to block processes producing the buffering capacity of the medium, among them possibly extrusion of organic acids.

• MeSH
• Potassium Chloride pharmacology   MeSH
• Hydrogen-Ion Concentration MeSH
• Acids metabolism   MeSH
• Deuterium Oxide pharmacology   MeSH
• Buffers MeSH
• Saccharomyces cerevisiae drug effects   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Potassium Chloride MeSH
• Acids MeSH
• Deuterium Oxide MeSH
• Buffers MeSH