Intracellular trehalase of a hybrid yeast.

1. The trehalase found in an extract prepared from a yeast strain that cannot ferment trehalose was studied and characterized. The enzyme is highly specific for trehalose with K(m) 1.02x10(-2)m, and an optimum pH of 6.9. 2. It is inhibited by glucose and by trehalose 6-phosphate, and does not facilitate any significant transglucosylations. 3. pK values 7.7 and 5.8 were detected for the groups associated with binding of the non-ionized substrate to the enzyme. 4. The trehalase was found to be highly labile and was inhibited by thiol-binding reagents. 5. The possible role of this enzyme in the trehalose-dissimilation patterns in the yeast cell was evaluated.