The effect of low temperature on the enzyme activities and the level of SH groups in benign gastric ulcer and gastric carcinoma.

Homogenates of human benign gastric ulcers and gastric carcinomas were stored at a low temperature (4 degrees C). The activities of L-lactate dehydrogenase (LDH), malic dehydrogenase (MDH), glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR) and the concentrations of SH-containing compounds showed changes. Increased activities of LDH, MDH, G6PDH and GR occurred in the gastric carcinomas stored at 4 degrees C compared with controls at 37 degrees C. In contrast, the activities of G6PDH and GR decreased in the tissues of benign gastric ulcers. On incubation at 4 degrees C the SH-containing compounds incorporated into protein molecules, SH groups binding with protein and non-protein SH groups decreased in both the benign and malignant tissues.