FIGURE 5.
Inhibition of maltose incorporation into glycogen by inorganic phosphate and arsenate. A, incubation mixtures contained buffer, glycogen, maltose-1-P, and enzyme as in Figs. 1 and 2 but also contained various amounts of sodium phosphate (■), sodium arsenate (▴), or sodium pyrophosphate (▾). After an incubation of 20 min, reactions were stopped with heating, and glycogen was isolated, and its radioactive content was determined. B, the incubations were similar to those in A except that the maltose-1-P concentration was increased 10-fold to 5 × 10−4 m to be above the Km value for this substrate. Both high (□) and low (●) maltose-1-P concentrations were run with arsenate as the inhibitor.