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Evidence for an inducible glucose transport system in Kluyveromyces lactis

1976; Elsevier BV; Volume: 426; Issue: 2 Linguagem: Inglês

10.1016/0005-2736(76)90339-4

1879-2642

Paulette W. Royt, Anthony M. MacQuillan,

Enzyme Catalysis and Immobilization

To find the cause of delayed glucose oxidation in succinate-grown Kluyveromyces lactis, glucose transport was studied in glucose- and in succinate-grown cells. The initial rate of 2-deoxyglucose (2-dGlc) accumulation, as well as the appearance of 2-deoxyglucose 6-phosphate, was higher in the glucose-grown cells. In both cell types, 2-dGlc was apparently transported in the free form to be phosphorylated intracellularly . In glucose-grown cells the level of free 2-dGlc in the pool was always less than the external concentration. Exchange transport in starved, poisoned cells loaded with unlabeled 2-dGlc was 140-fold greater in glucose- than in succinate-grown cells, probably because of the presence of an inducible transport component. The development of the increased rate of transport in a succinate-grown uracil-requiring auxotroph after transfer to glucose depends on the presence of uracil.