Global Profiling of Protein β-Hydroxybutyrylome in Porcine Liver

The liver orchestrates metabolic homeostasis through dynamic post-translational modifications. β-hydroxybutyrylation (Kbhb), a ketone body-driven modification, regulates epigenetics and metabolism in humans and mice but remains unexplored in livestock. Here, we characterize the porcine hepatic β-hydroxybutyrylome using high-resolution mass spectrometry, identifying 4982 Kbhb sites on 2122 proteins—the largest dataset to date. β-hydroxybutyrylation predominantly targets non-histone proteins (99.68%), with enrichment in fatty acid β-oxidation, TCA cycle, and oxidative phosphorylation pathways. Subcellular localization revealed cytoplasmic (38.1%), mitochondrial (18.1%), and nuclear (15.3%) dominance, reflecting BHB-CoA synthesis sites. Motif analysis identified conserved leucine, phenylalanine, and valine residues at modified lysines, suggesting enzyme-substrate specificity. β-hydroxybutyrate treatment elevated global Kbhb levels, increasing TCA intermediates (e.g., α-ketoglutarate, +9.56-fold) while reducing acetyl-CoA, indicating enhanced mitochondrial flux. Cross-species comparisons showed tissue-specific Kbhb distribution (nuclear in human cells vs. mitochondrial in mice), highlighting metabolic adaptations. This study establishes pigs as a model for Kbhb research, linking it to energy regulation and providing insights into metabolic reprogramming.