has role gamma-amino-beta-hydroxybutyric acid carnitine carnitinium A quaternary ammonium ion that is the the conjugate acid of carnitine. CHEBI:3424 Carnitine 3-carboxy-2-hydroxy-N,N,N-trimethylpropan-1-aminium KEGG:C00487 3-hydroxy-4-(trimethylammonio)butanoic acid quaternary ammonium ion mouse metabolite human metabolite