The Use of Phenolic Glycosides for Studying the Aerobic or Anaerobic Transport of Disaccharides into Yeasts

Nitrophenolic glycosides have been used to characterize the kinetics of anaerobic transport into yeasts. This procedure overcomes the problem of providing energy for anaerobic transport, when using non-metabolizable sugar analogues. The glycosides were hydrolysed intracellularly, the glycon catabolized, and the nitrophenol rapidly expelled from the cells. Transport was the rate-limiting metabolic step and involved proton symport. Experiments are described that establish the validity of the method, which is simple, quick, cheap and reliable, and seems generally applicable to yeasts. The high absorption coefficients of the nitrophenols allow precise measurements to be made at low concentrations, at which the proton-conducting properties of the nitrophenols are minimal.