title: In vitro reaction of beta-propiolactone and gamma-butyrolactone with glutathione and cysteine.
abstract: The in vitro reaction of the carcinogenic beta-propiolactone (BPL) and the non-carcinogenic gamma-butyrolactone (GBL) with glutathione (GSH) and cysteine (CySH) was examined spectrophotometrically. The characteristic absorbance of thioesters in the region of 233 nm appeared when BPL and GSH reacted but not when BPL and CySH reacted or when GBL was mixed with GSH or CySH. The absorbance disappeared when hydroxylamine was added. The results are in striking contrast to the notion that all carcinogenic lactones alkylate nucleophiles and that all inactive lactones acylate nucleophiles. The reaction between BPL and GSH produced about equal quantities of thioester and thioether, which could be separated chromatographically.
mesh_terms: D001665:Binding Sites; D002087:Butyrates; D003545:Cysteine; D005978:Glutathione; D006898:Hydroxylamines; D007700:Kinetics; D007783:Lactones; D011422:Propionates; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002087:Butyrates; D006898:Hydroxylamines; D007783:Lactones; D011422:Propionates; D005978:Glutathione; D003545:Cysteine