Loss of inducible D-galactose transport by baker's yeast after osmotic treatment.
The ability of Saccharomyces cerevisiae to transport D-galactose and related sugars with an axial hydroxyl group at C-4, acquired by induction with D-galactose, was lost either by exposing early exponential-phase cells to an osmotic shock involving incubation in 0.6M NaC1O4, 0.66M sucrose and 1mM histidine and transfer to 5mM Tris-HC1 with 2mM dithiothreitol, or simply by transferring them to distilled water. The total amount of protein thus released was 0.1--0.35 and 0.1 mg per mg dry wt., respectively. The shock fluid contained at least six proteins, among them a galactose-binding component. L-Arabinose transport could not be restored by adding the concentrated shock fluid to depleted cells but cells remained viable after the shock and resynthesized the transport system if incubated in a galactose-containing growth medium.
D001089:Arabinose / Q000378:metabolism; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000096:biosynthesis; D005690:Galactose / Q000378:metabolism*; D009995:Osmosis; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013237:Stereoisomerism; D014994:Xylose / Q000378:metabolism
D002352:Carrier Proteins; D005656:Fungal Proteins; D014994:Xylose; D001089:Arabinose; D005690:Galactose