ISSN:
1432-072X
Schlagwort(e):
Yeast
;
Hexose transport
;
Sugar
;
Malate uptake
;
2,4-DNP
;
Zygosaccharomyces bailii
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract When grown in fructose or glucose the cells of Zygosaccharomyces bailii were physiologically different. Only the glucose grown cells (glucose cells) possessed an additional transport system for glucose and malate. Experiments with transport mutants had lead to the assumption that malate and glucose were transported by one carrier, but further experiments proved the existence of two separate carrier systems. Glucose was taken up by carriers with high and low affinity. Malate was only transported by an uptake system and it was not liberated by starved malate-loaded cells, probably due to the low affinity of the intracellular anion to the carrier. The uptake of malate was inhibited by fructose, glucose, mannose, and 2-DOG but not by non metabolisable analogues of glucose. The interference of malate transport by glucose, mannose or 2-DOG was prevented by 2,4-dinitrophenol, probably by inhibiting the sugar phosphorylation by hexokinase. Preincubation of glucose-cells with metabolisable hexoses promoted the subsequent malate transport in a sugar free environment. Preincubation of glucose-cells with 2-DOG, but not with 2-DOG/2,4-DNP, decreased the subsequent malate transport. The existence of two separate transport systems for glucose and malate was demonstrated with specific inhibitors: malate transport was inhibited by sodium fluoride and glucose transport by uranylnitrate. A model has been discussed that might explain the interference of hexoses with malate uptake in Z. bailii.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00409715
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