Studies on acid soluble thiols in the human gastric juice.

Human gastric juice was found to contain high levels of thiols as detected by reaction with dithionitrobenzoic acid (Ellman's reagent). Analysis of gastric juice for glutathione and cysteine, the known acid soluble thiols in biological system, by HPLC and calorimetric methods, indicated that they are absent in the gastric juice. Further studies on the nature of thiols in the gastric juice, by Sephadex G-25 gel filtration indicated the presence of both high and low molecular weight protein and peptide associated thiols. Dialysis of the gastric juice retained nearly 70% thiols in non-dialysable fraction. These studies suggest that biologically important low molecular weight thiols, glutathione and cysteine are absent in the human gastric juice and the thiols detected are mainly acid soluble proteins and possibly peptide associated thiols.