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dc.contributor.authorBradford, Amanda.en_US
dc.date.accessioned2009-05-21T13:25:17Z
dc.date.available2009-05-21T13:25:17Z
dc.date.issued2002-05-21T13:25:17Z
dc.identifier.urihttp://hdl.handle.net/10464/1280
dc.description.abstractThe kinetic study of the coupled enzymatic reaction involving monomeric yeast hexokinase PII (HK) and yeast glucose-6-phosphate dehydrogenase (G-6-PDH) yields a Michaelis constant of 0.15 ± 0.01 mM for D-glucose. At pH 8.7 HK is present in monomeric form. The addition of polyethylene glycol (PEG), to the reaction mixture increased the affinity of HK for glucose, independent ofMW of the PEG from 2000 to 10000. The osmotic stress exerted by PEG can be used to measure the change in number of water molecules that accompany enzyme conformational changes (Rand, et al., 1993). Results indicate that the G-6-PDH is not osmotically sensitive and thus, the change in the number of PEG-inaccessible water molecules (ANw) measured in the coupled reaction is only the difference between the glucose-bound and glucosefree conformations of HK. ANw ~ 450 with PEGs of MW > 2000 under conditions for both binding (Reid and Rand, 1997) and kinetic assays. The contribution water may play in the binding of ATP (Km = 0.24 + 0.02 mM) has also been examined. It was found that in this case ANw = (for osmotic pressures < 2.8x10* dynes/cm^), suggesting no additional numbers of waters are displaced when ATP binds to HK. Osmotic pressure experiments were also performed with dimeric HK. It was determined that both the monomeric and dimeric forms of HK give the same ANw under low pressures. If this large ANw is due to conformational flexibility, it would appear that the flexibility is not reduced upon dimerization ofthe enzyme.en_US
dc.language.isoengen_US
dc.publisherBrock Universityen_US
dc.subjectGlucokinase.en_US
dc.subjectHydration.en_US
dc.subjectChemical kinetics.en_US
dc.titleHydration, conformational states and kinetics of yeast hexokinase PII /en_US
dc.typeElectronic Thesis or Dissertationen
dc.degree.nameM.Sc. Biological Sciencesen_US
dc.degree.levelMastersen_US
dc.contributor.departmentDepartment of Biological Sciencesen_US
dc.degree.disciplineFaculty of Mathematics and Scienceen_US
refterms.dateFOA2021-08-07T01:32:44Z


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