Abstract
Evidence is presented for the induction of an active transport system for the entry of glucose 6-phosphate into Escherichia coli B. This system was induced by growth on glucose 6-phosphate as sole carbon source and required active protein synthesis. The analogue, 2-deoxy- d-glucose 6-phosphate- 32P, was found to be accumulated by glucose 6-phosphate-grown cells. Energy was required for this process. The rate of accumulation of radioactivity in cells from added glucose 6-phosphate- 14C was found to be a useful measure of permease activity. A Km of 2.7 × 10 −4 m was estimated for glucose 6-phosphate entry into adapted cells. These studies also indicated that glucose-grown E. coli was completely impermeable to glucose 6-phosphate. Other hexose phosphates markedly inhibited the accumulation of glucose 6-phosphate, whereas l-α-glycerophosphate, fructose 1,6-diphosphate, and glucose had no effect. Glucose 1-phosphate- 14C was accumulated by glucose 6-phosphate-adapted cells. A microprocedure for the preparation of d-glucose 6-sulfate- 14C is presented. No accumulation of this analogue was found in glucose 6-phosphate-adapted cells.
Published Version
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