To test whether primitive hematopoietic stem cells (PHSCs) are stimulated by Steel (SI) factor (c-kit ligand) in vivo, donor mice were studied after three or seven daily injections of SI factor. PHSC activity was measured as long-term erythroid and lymphoid competitive repopulating ability. Cells to be tested (usually marrow or spleen cells from treated donors) were mixed with untreated competi...

Assessment of the relative importance of variation in enzyme concentration [E] and metabolic regulation in accounting for interspecific variation in metabolic rates is an unrealized area of research. Towards this end, we used metabolic flux rates during hovering and enzymatic flux capacities (V(max) values, equal to [E]xk(cat), where k(cat) is catalytic efficiency) in flight muscles measured in...

Cell-free biosystems comprised of synthetic enzymatic pathways would be a promising biomanufacturing platform due to several advantages, such as high product yield, fast reaction rate, easy control and access, and so on. However, it was essential to produce (purified) enzymes at low costs and stabilize them for a long time so to decrease biocatalyst costs. We studied the stability of the four r...

UNLABELLED Phosphomannose isomerase (pmi) gene isolated from Escherichia coli allows transgenic plants carrying it to convert mannose-6- phosphate (from mannose), a carbon source that could not be naturally utilized by plants into fructose-6-phosphate which can be utilized by plants as a carbon source. This conversion ability provides energy source to allow the transformed cells to survive on t...

Phosphoglucose isomerase (PGI) is a ubiquitous cytosolic enzyme that plays a key role in glycolysis. PGI is also a multifunctional protein that acts in the extracellular milieu as a potent mitogen/cytokine. Increased expression of PGI and its receptor has been found in a wide spectrum of malignancies and is associated with cancer progression and metastasis. In this study, the role of PGI in the...

Herein we present an analysis of the chemical function of a recombinant bifunctional phosphomannose isomerase/GDP-mannose pyrophosphorylase (manC) from Pyrococcus furiosus DSM 3638 and its use in the synthesis of guanidinediphospho-hexoses and a range of nucleotidediphospho-mannoses. This enzyme is unusually promiscuous in both its nucleotide triphosphate (NTP) and sugar-1-phosphate acceptance....

2-Deoxy-D-glucose-6-phosphate ketol-isomerase (EC 2.6.1.16) forms glucosamine-6-phosphate and glutamate from fructose-6-phosphate and glutamine and plays an important role in chitin synthesis in fungi. We have established a new assay for fungal ketol-isomerase activity that is amenable to high throughput screening to identify enzyme inhibitors. Aspergillus fumigatus crude lysate was incubated w...

Cryptosporidium parvum is one of several Cryptosporidium spp. that cause the parasitic infection cryptosporidiosis. Cryptosporidiosis is a diarrheal infection that is spread via the fecal-oral route and is commonly caused by contaminated drinking water. Triosephosphate isomerase is an enzyme that is ubiquitous to all organisms that perform glycolysis. Triosephosphate isomerase catalyzes the for...

The hyperthermophilic crenarchaeon Aeropyrum pernix contains phosphoglucose isomerase (PGI) activity. However, obvious homologs with significant identity to known PGIs could not be identified in the sequenced genome of this organism. The PGI activity from A. pernix was purified and characterized. Kinetic analysis revealed that, unlike all known PGIs, the enzyme catalyzed reversible isomerizatio...