DETERMINATION OF THE ETHYLENE-OXIDE ADDUCT S-(2-HYDROXYETHYL)CYSTEINEBY A FLUOROMETRIC HPLC METHOD IN ALBUMIN AND GLOBIN FROM HUMAN BLOOD

A new method has been developed for the quantification of 2-hydroxyeth ylated cysteine resulting as adduct in blood proteins after human expo sure to ethylene oxide, by reversed-phase HPLC with fluorometric detec tion. The specific adduct is analysed in albumin and in globin. After isolation of albumin and globin from blood, acid hydrolysis of the pro tein and precolumn derivatisation of the digest with 9-fluorenylmethox ycarbonylchloride, the levels of derivatised S-hydroxyethylcysteine ar e analysed by RP-HPLC and fluorescence detection, with a detection lim it of 8 nmol/g protein. Background levels of S-hydroxyethylcysteine we re quantified in both albumin and globin, under special consideration of the glutathione transferase GSTT1 and GSTM1 polymorphisms. GSTT1 po lymorphism had a marked influence on the physiological background alky lation of cysteine. While S-hydroxyethylcysteine levels in ''non-conju gators'' were between 15 and 50 nmol/g albumin, ''low conjugators'' di splayed levels between 8 and 21 nmol/g albumin, and ''high conjugators '' did not show levels above the detection limit. The human GSTM1 poly morphism had no apparent effect on background levels of blood protein 2-hydroxyethylation.