Glycogen branching in exercised Epm2a+/+ and Epm2a−/− mice. Glycogen branching was measured by iodine spectra (with absorbance normalized to 400 nm) as described under “Experimental Procedures” in samples from Epm2a+/+ (filled symbols) and Epm2a−/− (open symbols) mice. A, not run (NR, circles) and 3 h after exercise (triangles). B, not run (NR, circles) and 1 day after exercise (diamonds). C, not run (NR, circles) and 7 days after exercise (squares). D, branching was also monitored by HPAEC-PAD, which separated glucose polymers from 2 to 45 residues after isoamylase treatment. The percentage of chains longer than 15 residues is plotted as an index of the branching state of glycogen from wild type Epm2a+/+ mice (filled bars) or Epm2a−/− mice (open bars) under the indicated condition. Bars with the same letter are not significantly different from each other; different letters indicate p < 0.05.