Abstract
A method was developed for the determination of deuterated phenylalanine (Phe) and tyrosine (Tyr) in plasma after intravenous loading with heptadeuterated Phe (0.030 g/kg). Phenylthiohydantoinderivatives of the amino acids are formed and separated preparatiyely by High Pressure Liquid Chromatography. The ratio of deuterated and nondeuterated amino acids is determined by mass spectrometry. Metabolites in urine fractions are investigated by gaschromatography/mass spectrometry. Thus far blood profiles (O-24 hrs) of labelled Phe and Tyr have been established in one control, two hyperphenylalaninaemics and two phenylketonurics. Significant differences were observed between plasma profile of deuterated Phe of control and patients. Extensive hydroxylation of Phe could only be seen in the control. None of the common urinary metabolites of Phe contained measurable amounts of deuterium. The results are cornpaired with oral loading tests, residual hydroxylase activity and excretion rates of urinary metabolites.
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Trefz, F., Byrd, D., Schmitt, H. et al. 85: In Vivo Study of Heptadeutero—Phenylalanine Metabolism in Phenylketonurics and Hyperphenylalaninaemics. Pediatr Res 10, 884 (1976). https://doi.org/10.1203/00006450-197610000-00076
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DOI: https://doi.org/10.1203/00006450-197610000-00076
