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dc.contributor.authorDonahue, Janet Leeen
dc.date.accessioned2014-03-14T20:34:23Zen
dc.date.available2014-03-14T20:34:23Zen
dc.date.issued2000-04-10en
dc.identifier.otheretd-04272000-16290048en
dc.identifier.urihttp://hdl.handle.net/10919/31955en
dc.description.abstractIn Escherichia coli, the utilization of glycerol and sn-glycerol 3-phosphate is mediated by gene products of the glp regulon. The regulon encompasses five operons, including the glpFKX operon. Although glpF and glpK encode glycerol diffusion facilitator and glycerol kinase,respectively, the function of glpX was unknown. In the present work, we show that glpX encodes a fructose 1,6-bisphosphatase (FBPase), which catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and phosphate. The purified FBPase was dimeric, dependent on Mn2+ for activity and exhibited an apparent Km of 35 μM for fructose 1,6-bisphosphate. The enzyme was inhibited by ADP, ATP and phosphate and activated by PEP. The attributes of the glpX-encoded FBPase were different from those of the previously characterized E. coli FBPase encoded by fbp. Mutants deleted in fbp (Δfbp) display a growthnegative phenotype on gluconeogenic carbon sources such as glycerol, indicating the inability of chromosomal glpX+ to complement Δfbp. However, a Δfbp mutation was complemented by overexpression of glpX+. In contrast, a glpX mutant exhibited a growth-positive phenotype on glycerol, glucose or fructose media. Surprisingly, a double mutant strain glpX pfkA (6-phosphofructokinase I) was more inhibited in growth on glucose and glycerol media than the pfkA parent. Carbohydrate metabolism in the pfkA background may be affected by the glpXmediated change in fructose 6-phosphate/fructose 1,6-bisphosphate levels. FBPase activities of soluble proteins separated by non-denaturing PAGE were visualized, showing a novel (third) FBPase, perhaps encoded by the glpX homolog, yggF.en
dc.publisherVirginia Techen
dc.relation.haspartetd2.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectfructose 6-phosphateen
dc.subjectcarbon metabolismen
dc.subject6-bisphosphataseen
dc.subjectfructose 1en
dc.subjectglycerol 3-phosphate regulonen
dc.titlePurification and Characterization of glpX-Encoded Fructose 1,6-Bisphosphatase, a New Enzyme of the Glycerol 3-Phosphate Regulon of Escherichia colien
dc.typeThesisen
dc.contributor.departmentBiochemistry and Anaerobic Microbiologyen
dc.description.degreeMaster of Scienceen
thesis.degree.nameMaster of Scienceen
thesis.degree.levelmastersen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.disciplineBiochemistry and Anaerobic Microbiologyen
dc.contributor.committeechairLarson, Timothy J.en
dc.contributor.committeememberHess, John L.en
dc.contributor.committeememberGillaspy, Glenda E.en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04272000-16290048/en
dc.date.sdate2000-04-27en
dc.date.rdate2001-05-01en
dc.date.adate2000-05-01en


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