SIMULTANEOUS DETERMINATION OF URINARY CYSTATHIONINE, LANTHIONINE, S-(2-AMINOETHYL)-L-CYSTEINE AND THEIR CYCLIC-COMPOUNDS USING LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY WITH ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION

A measurement system for cystathionine (Cysta) lanthionine (LT), and S -(2-aminoethyl)-L-cysteine (AEC), and reduced products of their ketimi nes, perhydro-1,4-thiazepine-3,5-dicarboxylic acid (PHTZDC), 1,4-thiom orpholine-3,5-dicarboxylic acid (TMDA) and 1,4-thiomorpholine-3-carbox ylic acid (TMA) in the urine samples of a patient with cystathioninuri a and normal human subjects has been developed, using column liquid ch romatography-mass spectrometry. The recoveries were about 90-105% for Cysta, LT and AEC, and about 77-87% for PHTZDC, TMDA and TMA after ion -exchange treatment. The concentrations of Cysta and PHTZDC in the uri ne of a patient with cystathioninuria were much higher compared with t hose in the urine of normal human subjects. The concentrations of AEC and TMDA were almost the same. LT and TMA could not be detected in the urine samples by this method. This method proved useful for the deter mination of sulfur-containing amino acids and their cyclic compounds i n biological samples. (C) 1997 Elsevier Science B.V.