homocitrulline

homocitrulline (CAS No.: 1190-49-4) is a carbamoylated amino acid derivative and structural analog of citrulline that participates in mammalian urea cycle–related metabolic pathways and amino acid metabolism. It arises through post-translational carbamylation of lysine residues or through metabolic intermediates, and can be further converted via homoargininosuccinate to homoarginine, linking it to nitrogen handling and arginine-related pathways. Homocitrulline is recognized as an important biomarker associated with metabolic dysregulation, with elevated levels reported in conditions such as non-alcoholic fatty liver disease, hypercitrullinemia, and lysinuric protein intolerance, reflecting perturbations in hepatic metabolism and amino acid transport. Mechanistically, its accumulation is indicative of altered urea cycle flux, protein carbamylation processes, and mitochondrial or hepatic metabolic stress rather than direct receptor-mediated activity, and no well-defined molecular targets or classical pharmacological inhibition constants have been established. In biochemical and cellular studies, homocitrulline is widely employed to investigate urea cycle disorders, protein modification pathways, and metabolic dysfunction, including its role as a surrogate marker in omics-based profiling and disease modeling. In vitro and in vivo applications typically utilize concentration ranges tailored to experimental objectives, often spanning low micromolar to millimolar levels depending on the system, to assess its impact on metabolic flux, protein modification, and disease-associated phenotypes in cell-based assays and animal models.