To test whether primitive hematopoietic stem cells (PHSC) cycle rapidly during recovery from an initial 5-fluorouracil (5-FU) treatment, two doses of 5-FU were administered 1, 3, 5 or 8 days apart. Cells from treated marrow donors were mixed with untreated competitor marrow that would produce genetically distinguishable erythrocytes and lymphocytes, using hemoglobin (Hb) and glucosephosphate is...

Enzymes acting on the first carbon of n-glucose are specific for a particular anomer. Two well known cases are the glucose oxidase from Penicillium not&urn and glucose dehydrogenase from liver, both of them specific for @-glucose1 (I, 2). It is likely that enzymes acting at the same level of n-glucose 6-phosphate will also have an anomeric specificity, but there was no definite information on t...

The occurrence of charge variants of phosphohexose isomerase was elucidated in cancerous and, for comparison, in noncancerous tissues obtained from the same organ. Surgical specimens from 35 patients with gastrointestinal and mammary carcinoma were studied by means of the isoelectric focusing (IEF) technique. Differences in the IEF pattern could be demonstrated in 90% of the patients with gastr...

Electrophoretic variants of phosphoglucose isomerase (PGI) in Colias butterflies have been studied from field and laboratory viewpoints. The transmission pattern is that of a dimeric enzyme controlled by one structural gene locus. Populations usually harbor four to six allelic mobility classes. These mobility classes are shared among species complexes, though their frequencies differ widely. Pr...

Bacterial survival requires adaptation to different environmental perturbations such as exposure to antibiotics, changes in temperature or oxygen levels, DNA damage, and alternative nutrient sources. During adaptation, bacteria often develop beneficial mutations that confer increased fitness in the new environment. Adaptation to the loss of a major non-essential gene product that cripples growt...

We tested the hypothesis that kinetic differences among allelic variants of glucose-6-phosphate isomerase (GPI; D-glucose-6-phosphate ketol-isomerase, EC 5.3.1.9) from the sea anemone Metridium senile differentially modulate glucose metabolism at the glycolysis-pentose-shunt branch point. Fractional contribution of pentose shunt and absolute flux of glucose in glycolysis were measured in fasted...

Anaerobic stress in maize (Zea mays L.) leads to a drastic alteration in gene expression and results in the selective synthesis of a small number of polypeptides named anaerobic proteins (Sachs et al., 1980). Other plants studied showed similar responses when subjected to an anaerobic environment (Russell et al., 1990). To date, the majority of the anaerobic proteins that have been identified w...

Mutants of Escherichia coli defective in diglyceride kinase contain 10 to 20 times more sn-1,2-diglyceride than normal cells. This material constitutes about 8% of the total lipid in such strains. We now report that this excess diglyceride is recovered in the particulate fraction, primarily in association with the inner, cytoplasmic membrane. The diglyceride kinase of wild-type cells was recove...

Phosphoglucose isomerase (EC ) catalyzes the second step in glycolysis, the reversible isomerization of D-glucose 6-phosphate to D-fructose 6-phosphate. The reaction mechanism involves acid-base catalysis with proton transfer and proceeds through a cis-enediol(ate) intermediate. 5-Phospho-D-arabinonohydroxamic acid (5PAH) is a synthetic small molecule that resembles the reaction intermediate, d...

The glycolytic enzyme phosphoglucose isomerase catalyses the reversible isomerization of glucose 6-phosphate to fructose 6-phosphate. The phosphoglucose isomerase from the hyperthermophilic archaeon Pyrococcus furiosus, which shows no sequence similarity to any known bacterial or eukaryotic phosphoglucose isomerase, has been cloned and overexpressed in Escherichia coli, purified and subsequentl...