Calorimetric study on the sugar metabolism of yeast under nongrowing conditions.

Publisher Website
Google Scholar
Abstract
When glucose was added to a washed suspension of yeast under aerobic conditions, the heat production curve showed 3 distinct phases which reflect the metabolic process. The 1st phase showed a sharp peak which may be attributed to the uptake of glucose, the rate of which was proportional to the cell concentration. The results of chemical analyses suggest that the 2nd phase is connected to the metabolism of ethanol, which is followed by the 3rd phase of endogenous metabolism. The 2nd and 3rd phases were nearly absent under anaerobic conditions or when respiration was inhibited. The amount of cellular trehalose, which serves as an energy source, was reflected by the physiological state of the cells, but showed little effect on heat production. The heat produced was proportional to the glucose concentration, depending on the temperature. There were some differences between glucose metabolism and endogenous metabolism in the temperature effect on the rate of heat production. Some correlations between heat production and ATP were observed under anaerobic conditions, but no correlation was observed under aerobic conditions. A comparion was made of enthalpy change with different types of metabolism of yeast. The calorimetric measurements are considered to be a useful approach in studying sugar intake processes.