The enzymes of the Leloir pathway catalyze the conversion of galactose to a more metabolically useful version, glucose-6-phosphate. This pathway is required as galactose itself cannot be used for glycolysis directly. In most organisms, including the yeast Saccharomyces cerevisiae, five enzymes are required to catalyze this conversion: a galactose mutarotase, a galactokinase, a galactose-1-phosp...

Investigation of the structure/function relationships of the sodium-glucose transporter (SGLT1) is crucial to understanding the cotransporter mechanism. In the present study, we used cysteine-scanning mutagenesis and chemical modification by methanethiosulfonate (MTS) derivatives to test whether predicted transmembrane IV participates in sugar binding. Five charged and polar residues (K139, Q14...

1. The aerobic transport of d-glucose and d-galactose in rabbit kidney tissue at 25 degrees was studied. 2. In slices forming glucose from added substrates an accumulation of glucose against its concentration gradient was found. The apparent ratio of intracellular ([S](i)) and extracellular ([S](o)) glucose concentrations was increased by 0.4mm-phlorrhizin and 0.3mm-ouabain. 3. Slices and isola...

Lactose (1,4-O-beta-d-galactopyranosyl-d-glucose) is a soluble and economic carbon source for the industrial production of cellulases or recombinant proteins by Hypocrea jecorina (anamorph Trichoderma reesei). The mechanism by which lactose induces cellulase formation is not understood. Recent data showed that the galactokinase step is essential for cellulase induction by lactose, but growth on...

Phosphorylation of free galactose by lactic streptococci was mediated by an adenosine triphosphate (ATP)-dependent kinase. The phosphoenolpyruvate (PEP) phosphotransferase system (PTS) was involved to a limited extent in transport of the sugar. The conversion of free galactose to glucose also was demonstrated, and uridine diphosphogalactose-4-epimerase was demonstrated to account for this chang...

Some of the properties of a 70-fold purified bovine milk lactose synthetase have been determined. The enzyme preparation appears to be specific for uracil nucleoside diphosphate D-galactose derivatives. Adenosine, thymidine, @dine, or guanosine diphosphate derivatives cannot serve as galactosyl donors for n-glucose to form lactose. The enzyme preparation will not transfer the galactosyl residue...

Ten willow cultivars grown in experimental plots were evaluated for performance, attractiveness to foragers, and the content composition of soluble carbohydrates. The survival cuttings a thicket browse differed subject cultivar, soil quality, moisture content. number stump sprouts varied considerably, from 1.1 shoots weakest soils S?onin, Poland, 3.43 plot Czempin, Poland. Browse established 20...

We have expressed the human isoforms of the liver-type (GLUT2) and brain-type (GLUT3) facilitative glucose transporters in oocytes from Xenopus laevis via injection of in vitro transcribed mRNA. As reported previously [Gould, Thomas, Jess and Bell (1991) Biochemistry 30, 5139-5145], GLUT2 mediates the transport of fructose and galactose, and GLUT3 mediates the transport of galactose. We have ex...

1. Certain sugars were transported across the buccal mucosa by a carrier-mediated mechanism. 2. The metabolic loss of sugars from the mouth in a 5 min test period was negligible. 3. The buccal mucosal transport process was stereospecific for D-glucose and L-arabinose. 4. The absorption of D-glucose, galactose and 3-O-methyl-D-glucose was at least partly dependent on the presence of sodium ions ...

In this study we have investigated the effects of (a) chronic ethanol intake on glucose and galactose absorption across the rat jejunum in vivo and on the potential difference across the isolated brush border membrane (Vm) and (b) acute exposure to ethanol (4% or 8%) and acetaldehyde (0.25%) on changes in Vm associated with Na(+)-dependent galactose absorption across the jejunum and ileum. Chro...