Bisson L F, Fraenkel D G
J Bacteriol. 1984 Sep;159(3):1013-7. doi: 10.1128/jb.159.3.1013-1017.1984.
There are both low- and high-affinity mechanisms for uptake of glucose in Saccharomyces cerevisiae; high-affinity uptake somehow depends on the presence of hexose kinases (L. F. Bisson and D. G. Fraenkel, Proc. Natl. Acad. Sci. U.S.A. 80:1730-1734, 1983; L. F. Bisson and D. G. Fraenkel, J. Bacteriol. 155:995-1000, 1983). We report here on the effect of culture conditions on the level of high-affinity uptake. The high-affinity component was low during growth in high concentrations of glucose (100 mM), increased as glucose was exhausted from the medium, and decreased again during prolonged incubation in the stationary phase. The higher level of uptake was found in growth on low concentrations of glucose (0.5 mM) and in growth on normal concentrations of galactose, lactate plus glycerol, or ethanol. These results suggest that some component of high-affinity uptake is repressible by glucose. A shift from medium with 100 mM glucose to medium with 5 mM glucose resulted in up to a 10-fold increase in the level of high-affinity uptake within 90 min; the increase did not occur in the presence of cycloheximide or 2,4-dinitrophenol or in buffer alone with low glucose, suggesting that protein synthesis or energy metabolism (or both) was required. Reimposition of the high glucose concentration caused loss of high-affinity uptake, a process not prevented by cycloheximide. The use of hexokinase single-gene mutants showed that the derepression of high-affinity uptake was not clearly correlated with changes in levels of the kinases themselves. These results place the phenomenon of high- and low-affinity uptake in a physiological context, in that high-affinity uptake seems to be expressed best in conditions where it might be needed. Apparent similarities between glucose uptake in yeast and animal cells are noted.
酿酒酵母中存在低亲和力和高亲和力两种葡萄糖摄取机制；高亲和力摄取在某种程度上依赖于己糖激酶的存在（L.F.比松和D.G.弗伦克尔，《美国国家科学院院刊》80:1730 - 1734，1983；L.F.比松和D.G.弗伦克尔，《细菌学杂志》155:995 - 1000，1983）。我们在此报告培养条件对高亲和力摄取水平的影响。在高浓度葡萄糖（100 mM）中生长时，高亲和力成分较低，随着培养基中葡萄糖耗尽而增加，并在稳定期长时间培养期间再次降低。在低浓度葡萄糖（0.5 mM）中生长以及在正常浓度的半乳糖、乳酸加甘油或乙醇中生长时，摄取水平较高。这些结果表明，高亲和力摄取的某些成分可被葡萄糖抑制。从含100 mM葡萄糖的培养基转变为含5 mM葡萄糖的培养基，在90分钟内高亲和力摄取水平最多可增加10倍；在存在环己酰亚胺或2,4 -二硝基苯酚的情况下或仅在低葡萄糖缓冲液中不会出现这种增加，这表明需要蛋白质合成或能量代谢（或两者都需要）。重新施加高葡萄糖浓度会导致高亲和力摄取丧失，这一过程不受环己酰亚胺的阻止。使用己糖激酶单基因突变体表明，高亲和力摄取的去抑制与激酶自身水平的变化没有明显相关性。这些结果将高亲和力和低亲和力摄取现象置于生理背景中，因为高亲和力摄取似乎在可能需要的条件下表现最佳。文中指出了酵母和动物细胞中葡萄糖摄取之间明显的相似之处。
