IDENTIFICATION OF O-PHOSPHOAMINO ACIDS IN URINE HYDROLYSATE BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

The occurrence of O-phosphoserine (P-Ser), O-phosphothreonine (P-Thr) and O-phosphotyrosine (P-Tyr) in the hydrolysate of human urine was de monstrated. Urine samples were separated into non-adsorbed and adsorbe d fractions by DEAE-cellulose column chromatgraphy. After acid and bas e hydrolyses of these fractions, the O-phosphoamino acids in the hydro lysates were converted into their N-isobutoxycarbonyl methyl ester der ivatives and identified by gas chromatography-mass spectrometry. By ga s chromatography with flame photometric detection, the urinary content s of P-Ser, P-Thr and P-Tyr were estimated to be 945 +/- 3, 109 +/- 3 and 2.9 +/- 0.2 ng/ml, respectively.