Galactose Transport in Saccharomyces cerevisiae II. Characteristics of Galactose Uptake and Exchange in Galactokinaseless Cells
1970; American Society for Microbiology; Volume: 103; Issue: 3 Linguagem: Inglês
10.1128/jb.103.3.671-678.1970
ISSN1098-5530
AutoresShou-Chang Kou, Michael Christensen, Vincent P. Cirillo,
Tópico(s)Biochemical Acid Research Studies
ResumoThe characteristics of the inducible galactose system in Saccharomyces cerevisiae were studied by using the nonmetabolized galactose analogues, l -arabinose and d -fucose, and galactokinaseless and transportless mutants. Induced wild-type cells transport l -arabinose by facilitated diffusion. Transportless cells transport neither galactose nor l -arabinose above the noninduced rate, whereas galactokinaseless cells transport galactose l -arabinose and d -fucose by facilitated diffusion. Determination of unidirectional rate of 14 C-labeled galactose uptake by preloaded galactokinaseless cells, containing a large unlabeled free-galactose pool, showed that the rate of galactose uptake by facilitated diffusion is greater than the rate of galactose metabolism at similar external galactose concentrations.
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