In situ study of the glycolytic pathway in Saccharomyces cerevisiae.

1. The problem of the influence of protein concentration on the kinetic parameters of enzymes has been approached studying the glycolytic enzymes from Saccharomyces cerevisiae in permeabilized cells (in situ). 2. The values of Km and Vmax for the different enzymes were essentially the same in dilute solutions of protein and in concentrated ones (in situ) except in the case of enolase where some differences were observed. 3. Functioning of the whole glycolytic pathway was compared in situ and in vitro measuring the rate of the fermentation of glucose. The rate of fermentation in situ was two fold higher than in vitro and the lag before active fermentation was also much shorter. 4. An unidentified phosphorylated compound, possibly polyphosphate, accumulates during the fermentation of glucose under in situ conditions.