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Respiratory inhibitors affect incorporation of glucose into Saccharomyces cerevisiae cells, but not the activity of glucose transport
Author(s) -
Walsh Michael C.,
Smits HansPeter,
van Dam Karel
Publication year - 1994
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.320101204
Subject(s) - cyanide , hexose , intracellular , glucose uptake , biology , glucose transporter , biochemistry , carbohydrate metabolism , saccharomyces cerevisiae , snf3 , extracellular , galactose , fructose , incubation , respiration , metabolism , yeast , enzyme , chemistry , insulin , endocrinology , botany , inorganic chemistry
Incubation of starved galactose‐grown S. cerevisiae cells with cyanide reduced glucose uptake as measured over a 5‐s period. The V max for glucose uptake was decreased by over a factor of two but the apparent affinity for glucose doubled. When measured in the sub‐second time scale, however, there was no significant inhibition of glucose uptake, by cyanide, up to 200‐ms, clearly demonstrating that, in cyanide treated cells, glucose uptake was not linear for the first 5‐s. After a 200‐ms exposure of untreated cells to radio‐labelled glucose, less than 10% of the intracellular label resided in soluble uncharged compounds. In cyanide‐treated cells up to 43% of the labelled compounds were uncharged, with a concurrent reduction of intracellular label residing in anionic compounds. The results suggest that, in the presence of 10 mM cyanide when respiration is inhibited, a reduction in the cellular ATP concentration causes a reduction in hexose‐kinase activity which results in an accumulation of internal free glucose, which in turn causes a reduction in net glucose transport.