Protein carbamylation pathway

The protein carbamylation pathway is a non-enzymatic post-translational modification (PTM) characterized by the reaction between isocyanic acid and the free functional groups of proteins, particularly the N-terminus and lysine side chains (Jaisson et al., 2011, PMID: 21368018). Isocyanic acid is primarily generated through the spontaneous decomposition of urea or via the oxidation of thiocyanate by the enzyme myeloperoxidase (MPO) during inflammation (Wang et al., 2007, PMID: 17351645). This modification leads to the formation of homocitrulline, which alters protein conformation, charge, and biological activity, contributing to the progression of chronic kidney disease (CKD) and atherosclerosis (Verbrugge et al., 2015, PMID: 25855666). Carbamylated proteins, such as carbamylated LDL, are pro-atherogenic and serve as potent biomarkers for cardiovascular risk and uremic complications (Kalim et al., 2014, PMID: 24903351). Therapeutic strategies targeting this pathway focus on reducing cyanate levels through urea management, using competitive scavengers like glycine or lysine, or inhibiting MPO to prevent cyanate production (Morsy et al., 2023, PMID: 37443211). Although it is a biochemical process rather than a single receptor, its role in systemic protein damage makes it a critical area for drug development in metabolic and renal diseases. The accumulation of carbamylated products is also linked to immune system activation, as these modified proteins can act as neoantigens in conditions like rheumatoid arthritis (Trouw et al., 2017, PMID: 28838935). Monitoring homocitrulline levels provides a quantitative measure of cumulative uremic and oxidative stress over time.

Other names

Protein carbamoylationCyanate-mediated protein modificationUremia-induced protein modificationHomocitrullination

Therapeutic intervention involves the use of nucleophilic scavengers to neutralize reactive cyanate or the inhibition of enzymes like myeloperoxidase to prevent the oxidative formation of cyanate from thiocyanate.