NOVEL MODIFICATION OF 5-FORMYLURACIL BY CYSTEINE DERIVATIVES IN AQUEOUS-SOLUTION

Reactivities of 5-formyl-2'-deoxyuridine (fdU) and its 5'-monophosphat e (fdUMP) to amino acids, amines and thiol compounds in neutral aqueou s solution have been studied to elucidate the postmodification of the 5 formyluracil (fU) moiety in cells. fdU and fdUMP specifically reacte d with cysteine and its analogs to form thiazolidine derivatives. The reaction involved condensation of the formyl group of fU with both alp ha-NH2 (or NH2 at the equevalent position) and SH groups of cysteine d erivatives.