Galactose inhibition of the constitutive transport of hexoses in Saccharomyces cerevisiae
Article first published online: 29 JAN 2004
Copyright © 1993 John Wiley & Sons Ltd.
Volume 9, Issue 2, pages 111–119, February 1993
How to Cite
Nevado, J., Navarro, M. A. and Heredia, C. F. (1993), Galactose inhibition of the constitutive transport of hexoses in Saccharomyces cerevisiae. Yeast, 9: 111–119. doi: 10.1002/yea.320090202
- Issue published online: 29 JAN 2004
- Article first published online: 29 JAN 2004
- Manuscript Accepted: 12 AUG 1992
- Manuscript Received: 15 MAY 1992
- hexose transport;
- galactose inhibition;
- Saccharomyces cerevisiae
The relationship between the pathways of glucose and galactose utilization in Saccharomyces cerevisiae has been studied. Galactose (which is transported and phosphorylated by inducible systems) is a strong inhibitor of the utilization of glucose, fructose and mannose (which have the same constitutive transport and phosphorylation systems). Conversely, all these three hexoses inhibit the utilization of galactose, though with poor efficiency. These cross-inhibitions only occur in yeast adapted to galactose or in galactose-constitutive mutants.
The efficiency of galactose as inhibitor is even greater than the efficiencies of each of the other three hexoses to inhibit the utilization of each other. Phosphorylation is not involved in the inhibition and the transport of sugars is the affected step.
The cross-inhibitions between galactose and either glucose, fructose or mannose do not implicate utilization of one hexose at the expense of the other, as it occurs in the mutual interactions between the latter three sugars. It seems that, by growing the yeast in galactose, a protein component is synthesized, or alternatively modified, that once bound to either galactose or any one of the other three hexoses (glucose, fructose or mannose), cross-interacts respectively with the constitutive or the inducible transport systems, impairing their function.