Fig. 4

Absolute and relative acetylation levels of the H4(4–17) peptide (GKGGKGLGKGGAKR) in the liver of the Syrian hamster measured by LC-MS/MS. A Acetylation levels of the H4(4–17) peptide for unacetylated or acetylated at one, two, three, or four (all) lysine residues. The distribution (%) of the specific lysine residue (H4K5, H4K8, H4K12, and H4K16) for the singly acetylated H4(4–17) peptide is specified. B Relative levels of the unacetylated, single, or double acetylated H4(4–17) peptide. Data are represented as mean (relative to the mean of SE). C Distribution of the singly acetylated H4(4–17) peptide at the four lysine residues H4K5, H4K8, H4K12, and H4K16. Acetylation levels were measured for summer euthermia (SE), torpor late (TL), and arousal early (AE) hamsters (n = 4 per group). Acetylation levels of the single lysine residues are shown as percentage of the total H4(4–17) peptide. All relative levels are calculated compared to the mean of SE. Statistical analysis by Kruskal-Wallis with Dunn’s correction *P < 0.05, **P <0.01, ***P < 0.001, ****P < 0.00001