Type of Document Master's Thesis Author Hoang, Jane Vu Author's Email Address tranghtn00@hotmail.com URN etd-07282006-163303 Title Inactivation of Choline Oxidase by Irreversible Inhibitors or Storage Conditions Degree Master of Science Department Chemistry Advisory Committee
Advisor Name Title Giovanni Gadda Committee Chair Alfons A. Baumstark Committee Member Dabney W. Dixon Committee Member Keywords
- Choline Oxidase
- Flavoproteins
- Enzyme Inactivation
- Chemical Modification
- Phenylhydrazine
- Tetranitromethane
- Mechanism-based Inhibitors
- Hysteresis
Date of Defense 2006-07-14 Availability unrestricted Abstract Choline oxidase from Arthrobacter globiformis is a flavin-dependent enzyme that catalyzes the oxidation of choline to betaine aldehyde through two sequential hydride-transfer steps. The study of this enzyme is of importance to the understanding of glycine betaine biosynthesis found in pathogenic bacterial or economic relevant crop plants as a response to temperature and salt stress in adverse environment. In this study, chemical modification of choline oxidase using two irreversible inhibitors, tetranitromethane and phenylhydrazine, was performed in order to gain insights into the active site structure of the enzyme. Choline oxidase can also be inactivated irreversibly by freezing in 20 mM sodium phosphate and 20 mM sodium pyrophosphate at pH 6 and -20 oC. The results showed that enzyme inactivation was due to a localized conformational change associated with the ionization of a group in close proximity to the flavin cofactor and led to a complete lost of catalytic activity.Files
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access hoang_jane_v_200608_ms.pdf 768.39 Kb 00:03:33 00:01:49 00:01:36 00:00:48 00:00:04