Analysis of aminoimidazole ribosides by capillary electrophoresis — Diagnosing defects in second part of purine biosynthetic pathway

BackgroundOnly three inherited metabolic defects have been identified in purine de novo synthesis (PDNS). We present here CE methods for diagnosing defects in the second half of PDNS (from sixth to tenth enzymatic conversion) based on analysis of aminoimidazole ribosides – dephosphorylated intermediates – in urine.MethodsAssays were performed in an uncoated fused-silica capillary using two electrophoretic separation systems: 60 mmol/l borate — 2-amino-2-methyl-1-propanol–80 mmol/l sodium dodecylsulfate (pH 9.6) and 200 mmol/l phosphate — sodium (pH 1.8).ResultsThe reported conditions allowed separation of all metabolites from major urinary constituents with analysis time less than 10 min and separation efficiency of 220 and 350 thousands theoretical plates per meter for borate and phosphate system, respectively. The intra- and interday imprecisions were less than 4.4% and 9.9% CV. Potential usefulness of the methods was demonstrated on samples from a patient with adenylosuccinate lyase deficiency and Chinese hamster ovary cell lines defective in PDNS.ConclusionsCE is a useful and effective tool in the analysis of aminoimidazole ribosides which enables diagnosis of known as well as not so far identified inherited defects of PDNS pathway.