FIGURE 2: All the defining features of a futile cycle (i) are present in the full trehalose cycle (ii). Balancing upper- and lower-glycolytic fluxes during the initiation of glycolysis is achieved by a combination (iii) of features inherent in the trehalose cycle. The specific regulatory components include: (1) ATP hydrolysis and substrate removal and (2) T6P-mediated inhibition of hxk activity, which together slow down the upper-glycolytic flux, and (3) P_i liberation, which functions to stimulate lower glycolysis. Glc, glucose; G6P, glucose 6-phosphate; TREH, trehalose; tps2, trehalose 6-phosphate phosphatase.