DIETARY REGULATION OF GLYCOLYTIC ENZYMES .2. ADAPTIVE CHANGES IN HUMAN JEJUNUM

The specific effects of dietary sugars on human jejunal glycolytic enzymes were studied in normal volunteers and fasting obese patients. Fructokinase (ketohexokinase, EC 2.7.1.3), Fru-I-P aldolase (ketose-I-phosphate aldehyde-lyase, EC 4.1.2.7), hexokinase (ATP: D-hexose 6-phosphotransferase, EC 2.7.1.1), glucokinase (ATP: D-hexose 6-phosphotransferase, EC 2.7.1.2), and Fru-I,6-P2 aldolase (fructose-I,6-diphosphate D-glyceraldehyde-3-phosphate-lyase, EC 4.1.2.13) were measured. Fructose feeding had a specific effect on fructokinase and Fru-I-P aldolase whereas glucose had its major effect on hexokinase and glucokinase. Sucrose gave results intermediate between glucose and fructose. Carbohydrate-free diets gave results intermediate between fasting and carbohydrate diets. There were different responses of the Fru-I-P and Fru-I,6-P2 aldolases to different dietary sugars. These data indicate that specific dietary sugars can increase specific jejunal glycolytic enzymes in the human. © 1968.