Disease relevance of L-Homocitrulline

• A liquid chromatography tandem mass spectrometric method is described for the analysis of homocitrulline in human urine, a key metabolite in the differential diagnosis of hyperammonemia, hyperornithinemia, homocitrullinuria (HHH) syndrome [1].
• Antihomocitrulline antibodies identified homocitrulline (epsilon-amino-carbamoyl lysine) in situ in proteins in neutrophils in end stage renal disease [2].
• DESIGN: Anti-homocitrulline antibody is specific for homocitrulline and was used to identify carbamoylation of epsilon-amino-lysine in renal biopsies from patients with elevated BUN, with isolated proteinuria, and as controls, from normal donors at time of transplantation [3].

High impact information on L-Homocitrulline

• In search of useful lysine derivatives, we studied in patients with LPI the absorption after oral administration of homocitrulline and epsilon N-acetyllysine [4].
• Determination of citrulline and homocitrulline by high-performance liquid chromatography with post-column derivatization [5].
• The kinetics of homocitrulline formation was quite complicated, but an approximation was possible as the initial formation reaction could be modelled using zero order reaction kinetics [6].
• Homocitrulline, liberated from milk protein by enzymic hydrolysis, was eluted well separated from other amino acids and could be readily distinguished using this technique [6].
• The apparent activation energy for homocitrulline formation was estimated at approximately 90 kJ/mol [6].

Biological context of L-Homocitrulline

• Active transport could be involved with the small intestine assuming that L-homocitrulline has a low affinity for the carrier system [7].

Anatomical context of L-Homocitrulline

• 2. Metabolic inhibitors decreased L-homocitrulline uptake across the small intestine [7].
• RESULTS: Erythrocytes from uremic patients were found to have a greater level of carbamylation than those from nonuremic patients (47.09 +/- 7.80 and 25.89 +/- 6.92 nmol homocitrulline/mg proteolyzed protein released, respectively) [8].
• Absorption of homocitrulline from the gastrointestinal tract [7].
• Increased levels of ammonia, ornithine and homocitrulline were demonstrated in blood and cerebrospinal fluid [9].
• This suggests that homocitrulline is located in carbamoylated proteins within the perinuclear membrane, a structural organelle continuous with the endoplasmic reticulum [10].

Associations of L-Homocitrulline with other chemical compounds

• DESIGN AND METHODS: For in vivo studies, erythrocyte ghosts were digested with proteinase K and the released peptides colorimetrically assayed for carbamylation, using the diacetyl monoxime reagent, and quantitated using homocitrulline [8].

Gene context of L-Homocitrulline

• Further evidence for a separate enzymic entity for the synthesis of homocitrulline, distinct from the regular ornithine transcarbamylase [11].
• The fact that homocitrulline excretion is not observed in OTC deficiency suggests that the activity responsible for homocitrulline excretion is closely related to OTC [12].

Analytical, diagnostic and therapeutic context of L-Homocitrulline

• Total plasma protein carbamylation and plasma cLDL were measured in hemodialysis patients using the homocitrulline assay and enzyme-linked immunosorbent assay (ELISA) [13].
• Oral administration of epsilon N-acetyllysine and homocitrulline in lysinuric protein intolerance [4].

References