Intracellular buffering capacity

Range 75 to 180 figure - link ng ion H+/pH unit/mg cell dry weight
Organism Bacteria Staphylococcus aureus
Reference Collins SH, Hamilton WA. Magnitude of the protonmotive force in respiring Staphylococcus aureus and Escherichia coli. J Bacteriol. 1976 Jun126(3):1224-31. p.1227 fig.1PubMed ID7546
Method Caption of fig.1:"Buffering powers of extracellular (Bo [black triangle]), intracellular (Bi •), and total space (BT black square), of a suspension of S. aureus. Cells were harvested in exponential phase and allowed to equilibrate at a cell density of 0.83 mg/ml in sucrose-choline chloride-potassium chloride buffer as described in Materials and Methods. Bo was determined from the instantaneous change in pH on addition of anaerobic HCl. BT was determined from the change in pH on addition of HCl to cells treated with valinomycin and TCS (2µg/ml each). Bi is the difference between Bo and BT." Value extracted visually from fig.1
Comments "The purpose of the experiments reported in this communication was to obtain a measure of the magnitude of the protonmotive force that is developed across the cytoplasmic membrane of respiring Staphylococcus aureus and Escherichia coli." "Figure 1 shows typical experimental curves of the buffering power (dH+/ dpH) of a suspension of cells of S. aureus expressed as nanogram-ions of H+ per pH unit per milligram of cells (dry weight)."
Entered by Uri M
ID 107126