FIGURE 3.

Time course of inhibition of PFK-1 activity by S-hexadecyl-CoA in rabbit muscle cytosol. Isolated rabbit muscle cytosol (0.5 mg/ml) in 100 mm Tris-HCl, pH 7.5, containing 1 mm DTT was incubated with either 0, 5, or 10 μm S-hexadecyl-CoA for the indicated times at 30 °C. PFK-1 catalytic activity was then determined using a coupled spectrophotometric assay measuring the rate of NADH oxidation employing aldolase, triose-phosphate isomerase, and glycerol-3-phosphate dehydrogenase as described under “Experimental Procedures.” Results presented are the mean ± S.E. from at least three separate experiments.