O6-alkyltransferase activity in normal human gastric mucosa.

The spectrum of activity of the DNA repair enzyme O6-alkyltransferase has been studied in a large series of normal stomachs in order to establish the baseline range of values for this enzyme. Sixty-eight patients with histologically normal stomachs were biopsied during the course of upper gastrointestinal endoscopy and the biopsies assayed for O6-alkyl-transferase activity. A wide spectrum of activity was found with values ranging from 38 fmol O6-guanine extracted/mg protein to over 400 fmol/mg. This suggests that there may be wide inter-individual differences in susceptibility to alkylating actions in the human gastric mucosa.